diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..8eaa9db
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+/source
\ No newline at end of file
diff --git a/42/media/lua/shared/WaterpipesB42Patch.lua b/42/media/lua/shared/WaterpipesB42Patch.lua
new file mode 100644
index 0000000..14365df
--- /dev/null
+++ b/42/media/lua/shared/WaterpipesB42Patch.lua
@@ -0,0 +1,887 @@
+WaterpipesB42Patch = WaterpipesB42Patch or {}
+
+local Patch = WaterpipesB42Patch
+local Z_OFFSETS = {0, -1, 1, 2, 3}
+
+local function parseSquareKey(tileKey)
+    local x, y, z = string.match(tileKey, "^(-?%d+),(-?%d+),(-?%d+)$")
+    if not x then
+        x, y, z = string.match(tileKey, "^(-?%d+)-(-?%d+)-(-?%d+)$")
+    end
+    if not x then
+        return nil, nil, nil
+    end
+    return tonumber(x), tonumber(y), tonumber(z)
+end
+
+local function getVerticalSearchSquares(square)
+    local squares = {}
+    if not square then
+        return squares
+    end
+
+    local cell = square:getCell()
+    local sx, sy, sz = square:getX(), square:getY(), square:getZ()
+    local seen = {}
+
+    for _, offset in ipairs(Z_OFFSETS) do
+        local z = sz + offset
+        local key = tostring(z)
+        if not seen[key] then
+            seen[key] = true
+            local sq = cell and cell:getGridSquare(sx, sy, z) or nil
+            if sq then
+                table.insert(squares, sq)
+            end
+        end
+    end
+
+    return squares
+end
+
+local function findNearbyLinkedBid(square, xyRadius, zRadius)
+    if not square or not GetWPModData or not WPUtils or not WPUtils.Coords2Id then
+        return nil
+    end
+
+    local gmd = GetWPModData()
+    if not gmd then
+        return nil
+    end
+
+    local sx, sy, sz = square:getX(), square:getY(), square:getZ()
+    local zr = zRadius or 1
+    local rr = xyRadius or 1
+
+    for dz = -zr, zr do
+        local z = sz + dz
+        for dy = -rr, rr do
+            for dx = -rr, rr do
+                local x = sx + dx
+                local y = sy + dy
+                local id = WPUtils.Coords2Id(x, y, z)
+
+                local buildingNode = gmd.Buildings and gmd.Buildings[id] or nil
+                if buildingNode and buildingNode.bid and buildingNode.bid ~= "" then
+                    return buildingNode.bid
+                end
+
+                local barrelNode = gmd.Barrels and gmd.Barrels[id] or nil
+                if barrelNode and barrelNode.bid and barrelNode.bid ~= "" then
+                    return barrelNode.bid
+                end
+            end
+        end
+    end
+
+    return nil
+end
+
+local function getBuildingBidFromDef(def)
+    if not def then
+        return nil
+    end
+
+    local bid = def:getIDString()
+    if bid and bid ~= "" then
+        return bid
+    end
+    return nil
+end
+
+local function getBuildingBidFromObject(building)
+    if not building then
+        return nil, nil
+    end
+
+    local def = building:getDef()
+    local bid = getBuildingBidFromDef(def)
+    if bid then
+        return bid, def
+    end
+
+    if building.getID then
+        local id = building:getID()
+        if id ~= nil then
+            return "WPBuilding_" .. tostring(id), nil
+        end
+    end
+
+    return nil, nil
+end
+
+local function getRoomSignature(room, square)
+    local rects = room and room.getRects and room:getRects()
+    if rects and rects:size() > 0 then
+        local minX, minY, minZ
+        local maxX, maxY, maxZ
+
+        for i = 0, rects:size() - 1 do
+            local rect = rects:get(i)
+            local rx1, ry1 = rect:getX(), rect:getY()
+            local rx2, ry2 = rect:getX2(), rect:getY2()
+            local rz = square:getZ()
+            if rect.getZ then
+                rz = rect:getZ()
+            end
+
+            if not minX then
+                minX, minY, minZ = rx1, ry1, rz
+                maxX, maxY, maxZ = rx2, ry2, rz
+            else
+                if rx1 < minX then minX = rx1 end
+                if ry1 < minY then minY = ry1 end
+                if rz < minZ then minZ = rz end
+
+                if rx2 > maxX then maxX = rx2 end
+                if ry2 > maxY then maxY = ry2 end
+                if rz > maxZ then maxZ = rz end
+            end
+        end
+
+        return tostring(minX) .. "_" .. tostring(minY) .. "_" .. tostring(minZ) .. "_" ..
+            tostring(maxX) .. "_" .. tostring(maxY) .. "_" .. tostring(maxZ)
+    end
+
+    return tostring(square:getX()) .. "_" .. tostring(square:getY()) .. "_" .. tostring(square:getZ())
+end
+
+local function getBuildingDescriptorFromPoweredSquares(square)
+    if not ModData or not ModData.getOrCreate then
+        return nil
+    end
+
+    local modData = ModData.getOrCreate("PoweredBuildings_Squares")
+    if not modData or not modData.PoweredSquares then
+        return nil
+    end
+
+    local searchSquares = getVerticalSearchSquares(square)
+    for _, sq in ipairs(searchSquares) do
+        local squareKey = sq:getX() .. "," .. sq:getY() .. "," .. sq:getZ()
+        local selectedGenKey, selectedSquares = nil, nil
+
+        for genKey, poweredSquares in pairs(modData.PoweredSquares) do
+            if poweredSquares and poweredSquares[squareKey] then
+                local genKeyStr = tostring(genKey)
+                if not selectedGenKey or genKeyStr < selectedGenKey then
+                    selectedGenKey = genKeyStr
+                    selectedSquares = poweredSquares
+                end
+            end
+        end
+
+        if selectedGenKey then
+            return {
+                bid = "WPGen_" .. selectedGenKey,
+                poweredSquares = selectedSquares,
+            }
+        end
+    end
+
+    return nil
+end
+
+local function getBuildingDescriptorFromRoom(square)
+    local searchSquares = getVerticalSearchSquares(square)
+    for _, sq in ipairs(searchSquares) do
+        local room = sq:getRoom()
+        if room then
+            return {
+                bid = "WPRoom_" .. getRoomSignature(room, sq),
+                room = room,
+            }
+        end
+    end
+
+    return nil
+end
+
+local function patchWPIso()
+    if not WPIso or not WPVirtual or not WPUtils then
+        return false
+    end
+
+    if WPIso.__WaterpipesB42PatchApplied then
+        return true
+    end
+
+local function getBuildingDescriptorAtSquare(square)
+    if not square then
+        return nil
+    end
+
+    -- Prefer existing linked IDs to keep all taps in one network bid.
+    local linkedBid = findNearbyLinkedBid(square, 2, 1)
+    if linkedBid then
+        return { bid = linkedBid }
+    end
+
+    local searchSquares = getVerticalSearchSquares(square)
+        for _, sq in ipairs(searchSquares) do
+            local building = sq:getBuilding()
+            if building then
+                local bid, def = getBuildingBidFromObject(building)
+                if bid then
+                    return {
+                        bid = bid,
+                        building = building,
+                        def = def,
+                    }
+                end
+            end
+        end
+
+        local poweredDescriptor = getBuildingDescriptorFromPoweredSquares(square)
+    if poweredDescriptor then
+        return poweredDescriptor
+    end
+
+    return getBuildingDescriptorFromRoom(square)
+end
+
+WPIso.GetBuildingDescriptor = function(square)
+    if not square then
+        return nil
+    end
+
+    local descriptor = getBuildingDescriptorAtSquare(square)
+    if descriptor then
+        return descriptor
+    end
+
+    -- Fallback for moveables/taps placed on edge or outside-flagged tiles:
+    -- scan neighboring squares and resolve against the nearest valid descriptor.
+    local cell = square:getCell()
+    local sx, sy, sz = square:getX(), square:getY(), square:getZ()
+    for dy = -1, 1 do
+        for dx = -1, 1 do
+            if not (dx == 0 and dy == 0) then
+                local nsq = cell and cell:getGridSquare(sx + dx, sy + dy, sz) or nil
+                if nsq then
+                    descriptor = getBuildingDescriptorAtSquare(nsq)
+                    if descriptor then
+                        return descriptor
+                    end
+                end
+            end
+        end
+    end
+
+    -- Final fallback: slightly wider linked-bid scan.
+    local linkedBid = findNearbyLinkedBid(square, 4, 2)
+    if linkedBid then
+        return { bid = linkedBid }
+    end
+
+    return nil
+end
+
+    WPIso.GetBuildingBid = function(square)
+        local descriptor = WPIso.GetBuildingDescriptor(square)
+        if descriptor then
+            return descriptor.bid
+        end
+        return nil
+    end
+
+    WPIso.GetBuilding = function(square)
+        return WPIso.GetBuildingDescriptor(square)
+    end
+
+    WPIso.ConnectBuilding = function(square, building)
+        if not square then
+            return
+        end
+
+        local sx, sy, sz = square:getX(), square:getY(), square:getZ()
+        local cell = square:getCell()
+
+        local descriptor = building
+        if descriptor and descriptor.getDef then
+            local bid, def = getBuildingBidFromObject(descriptor)
+            descriptor = {
+                bid = bid,
+                building = descriptor,
+                def = def,
+            }
+        elseif not descriptor then
+            descriptor = WPIso.GetBuildingDescriptor(square)
+        end
+
+        if not descriptor or not descriptor.bid then
+            return
+        end
+
+        local bid = descriptor.bid
+        local traversed = {}
+
+        local function syncBarrelInSquare(sq)
+            if not sq then
+                return
+            end
+
+            local x, y, z = sq:getX(), sq:getY(), sq:getZ()
+            local key = WPUtils.Coords2Id(x, y, z)
+            if traversed[key] then
+                return
+            end
+            traversed[key] = true
+
+            local isoBarrel = WPIso.GetBarrel(sq)
+            if isoBarrel then
+                local _, wmax = WPIso.GetWaterStatus(isoBarrel)
+                WPVirtual.BarrelAdd(x, y, z, wmax * 100, bid)
+            end
+        end
+
+        if descriptor.def then
+            local def = descriptor.def
+            local bx1, bx2 = def:getX(), def:getX2()
+            local by1, by2 = def:getY(), def:getY2()
+            local bz1, bz2 = def:getMinLevel(), def:getMaxLevel()
+
+            for z = bz1, bz2 do
+                for y = by1, by2 do
+                    for x = bx1, bx2 do
+                        syncBarrelInSquare(cell:getGridSquare(x, y, z))
+                    end
+                end
+            end
+        elseif descriptor.poweredSquares then
+            for tileKey, _ in pairs(descriptor.poweredSquares) do
+                local x, y, z = parseSquareKey(tileKey)
+                if x and y and z then
+                    syncBarrelInSquare(cell:getGridSquare(x, y, z))
+                end
+            end
+        elseif descriptor.room then
+            local room = descriptor.room
+            local rects = room:getRects()
+            if rects then
+                for i = 0, rects:size() - 1 do
+                    local rect = rects:get(i)
+                    local rx1, ry1 = rect:getX(), rect:getY()
+                    local rx2, ry2 = rect:getX2(), rect:getY2()
+                    local rz = sz
+                    if rect.getZ then
+                        rz = rect:getZ()
+                    end
+
+                    for y = ry1, ry2 do
+                        for x = rx1, rx2 do
+                            local sq = cell:getGridSquare(x, y, rz)
+                            if sq and sq:getRoom() == room then
+                                syncBarrelInSquare(sq)
+                            end
+                        end
+                    end
+                end
+            end
+        end
+
+        WPVirtual.BuildingAdd(sx, sy, sz, bid)
+    end
+
+    if not WPVirtual.__WaterpipesB42PatchApplied then
+        local originalBarrelAdd = WPVirtual.BarrelAdd
+        WPVirtual.BarrelAdd = function(x, y, z, wmax, bid)
+            if (not bid or bid == "") and WPIso and WPIso.GetBuildingBid and getCell then
+                local sq = getCell():getGridSquare(x, y, z)
+                if sq then
+                    bid = WPIso.GetBuildingBid(sq)
+                end
+            end
+            return originalBarrelAdd(x, y, z, wmax, bid)
+        end
+        WPVirtual.__WaterpipesB42PatchApplied = true
+    end
+
+    WPIso.__WaterpipesB42PatchApplied = true
+    return true
+end
+
+local function tryApplyPatch()
+    if Patch.applied then
+        return
+    end
+
+    if patchWPIso() then
+        Patch.applied = true
+    end
+end
+
+local TRACE_MATRIX = {
+    ne = { n = {{x=1,y=0,z=0}}, e = {{x=0,y=-1,z=0}} },
+    se = { s = {{x=1,y=0,z=0}}, e = {{x=0,y=1,z=0}} },
+    sw = { s = {{x=-1,y=0,z=0}}, w = {{x=0,y=1,z=0}} },
+    nw = { n = {{x=-1,y=0,z=0}}, w = {{x=0,y=-1,z=0}} },
+    ns = { n = {{x=0,y=1,z=0}}, s = {{x=0,y=-1,z=0}} },
+    we = { w = {{x=1,y=0,z=0}}, e = {{x=-1,y=0,z=0}} },
+    nd = { n = {{x=0,y=0,z=-1}}, d = {{x=0,y=-1,z=0}} },
+    sd = { s = {{x=0,y=0,z=-1}}, d = {{x=0,y=1,z=0}} },
+    wd = { w = {{x=0,y=0,z=-1}}, d = {{x=-1,y=0,z=0}} },
+    ed = { e = {{x=0,y=0,z=-1}}, d = {{x=1,y=0,z=0}} },
+    nu = { n = {{x=0,y=0,z=1}}, u = {{x=0,y=-1,z=0}} },
+    su = { s = {{x=0,y=0,z=1}}, u = {{x=0,y=1,z=0}} },
+    wu = { w = {{x=0,y=0,z=1}}, u = {{x=-1,y=0,z=0}} },
+    eu = { e = {{x=0,y=0,z=1}}, u = {{x=1,y=0,z=0}} },
+    nsw = { n = {{x=-1,y=0,z=0},{x=0,y=1,z=0}}, s = {{x=-1,y=0,z=0},{x=0,y=-1,z=0}}, w = {{x=0,y=-1,z=0},{x=0,y=1,z=0}} },
+    swe = { s = {{x=-1,y=0,z=0},{x=1,y=0,z=0}}, w = {{x=1,y=0,z=0},{x=0,y=1,z=0}}, e = {{x=-1,y=0,z=0},{x=0,y=1,z=0}} },
+    nse = { n = {{x=1,y=0,z=0},{x=0,y=1,z=0}}, s = {{x=1,y=0,z=0},{x=0,y=-1,z=0}}, e = {{x=0,y=-1,z=0},{x=0,y=1,z=0}} },
+    nwe = { n = {{x=-1,y=0,z=0},{x=1,y=0,z=0}}, w = {{x=1,y=0,z=0},{x=0,y=-1,z=0}}, e = {{x=-1,y=0,z=0},{x=0,y=-1,z=0}} },
+    nswe = { n = {{x=-1,y=0,z=0},{x=1,y=0,z=0},{x=0,y=1,z=0}}, s = {{x=-1,y=0,z=0},{x=1,y=0,z=0},{x=0,y=-1,z=0}}, w = {{x=0,y=-1,z=0},{x=0,y=1,z=0},{x=1,y=0,z=0}}, e = {{x=0,y=-1,z=0},{x=0,y=1,z=0},{x=-1,y=0,z=0}} },
+}
+
+local function countEntries(t)
+    local c = 0
+    for _ in pairs(t) do
+        c = c + 1
+    end
+    return c
+end
+
+local function getTraceVectors(shape, dir)
+    local vectors = {}
+    local shapeData = TRACE_MATRIX[shape]
+    if shapeData and shapeData[dir] then
+        for _, vector in ipairs(shapeData[dir]) do
+            local d
+            if vector.x == 1 then d = "w" end
+            if vector.x == -1 then d = "e" end
+            if vector.y == 1 then d = "n" end
+            if vector.y == -1 then d = "s" end
+            if vector.z == 1 then d = "d" end
+            if vector.z == -1 then d = "u" end
+
+            table.insert(vectors, {x = vector.x, y = vector.y, z = vector.z, d = d})
+        end
+    end
+    return vectors
+end
+
+local function addDebugTile(set, x, y, z, symbol)
+    local id = WPUtils and WPUtils.Coords2Id and WPUtils.Coords2Id(x, y, z) or (tostring(x) .. "-" .. tostring(y) .. "-" .. tostring(z))
+    if not set[id] then
+        set[id] = {x = x, y = y, z = z, symbol = symbol}
+    end
+end
+
+local function tracePumpNetwork(gmd, pump)
+    local traced = {
+        pump = pump,
+        pipes = {},
+        targets = {},
+        closedValves = {},
+    }
+
+    local dirs = {
+        w = {x=1, y=0, z=0},
+        e = {x=-1, y=0, z=0},
+        n = {x=0, y=1, z=0},
+        s = {x=0, y=-1, z=0},
+    }
+
+    local stack = {}
+    for dir, vector in pairs(dirs) do
+        table.insert(stack, {x = pump.x + vector.x, y = pump.y + vector.y, z = pump.z + vector.z, dir = dir, depth = 0})
+    end
+
+    local visited = {}
+    local buildingBidsExpanded = {}
+    local safety = 0
+
+    while #stack > 0 do
+        local state = table.remove(stack)
+        safety = safety + 1
+        if safety > 5000 then
+            break
+        end
+
+        local stateKey = tostring(state.x) .. ":" .. tostring(state.y) .. ":" .. tostring(state.z) .. ":" .. tostring(state.dir)
+        if not visited[stateKey] and state.depth <= 128 then
+            visited[stateKey] = true
+
+            local nodeId = WPUtils.Coords2Id(state.x, state.y, state.z)
+            local pipe = gmd.Pipes[nodeId]
+            local barrel = gmd.Barrels[nodeId]
+            local building = gmd.Buildings[nodeId]
+
+            if pipe then
+                addDebugTile(traced.pipes, state.x, state.y, state.z, ".")
+
+                if gmd.Sprinklers[nodeId] then
+                    addDebugTile(traced.targets, state.x, state.y, state.z, "S")
+                end
+
+                local valve = gmd.Valves[nodeId]
+                if valve and valve.c then
+                    addDebugTile(traced.closedValves, state.x, state.y, state.z, "X")
+                else
+                    local vectors = getTraceVectors(pipe.s, state.dir)
+                    for _, vector in ipairs(vectors) do
+                        table.insert(stack, {
+                            x = state.x + vector.x,
+                            y = state.y + vector.y,
+                            z = state.z + vector.z,
+                            dir = vector.d,
+                            depth = state.depth + 1
+                        })
+                    end
+                end
+            elseif building then
+                addDebugTile(traced.targets, state.x, state.y, state.z, "B")
+
+                if building.bid and not buildingBidsExpanded[building.bid] then
+                    buildingBidsExpanded[building.bid] = true
+                    for _, barrelNode in pairs(gmd.Barrels) do
+                        if barrelNode.bid == building.bid then
+                            addDebugTile(traced.targets, barrelNode.x, barrelNode.y, barrelNode.z, "T")
+                        end
+                    end
+                end
+            elseif barrel then
+                addDebugTile(traced.targets, state.x, state.y, state.z, "R")
+            end
+        end
+    end
+
+    traced.pipeCount = countEntries(traced.pipes)
+    traced.targetCount = countEntries(traced.targets)
+    traced.closedValveCount = countEntries(traced.closedValves)
+
+    return traced
+end
+
+Patch.debugOverlay = Patch.debugOverlay or {
+    enabled = false,
+    recomputeEveryTicks = 30,
+    tick = 0,
+    cache = {},
+    unbound = {},
+    missingWorld = {},
+}
+
+local function isDebugModeEnabled()
+    if isDebugEnabled then
+        local ok, enabled = pcall(isDebugEnabled)
+        if ok and enabled then
+            return true
+        end
+    end
+
+    local core = getCore and getCore() or nil
+    if core then
+        if core.isDebug then
+            local ok, enabled = pcall(function() return core:isDebug() end)
+            if ok and enabled then
+                return true
+            end
+        end
+        if core.getDebug then
+            local ok, enabled = pcall(function() return core:getDebug() end)
+            if ok and enabled then
+                return true
+            end
+        end
+    end
+
+    return false
+end
+
+local function scanAndRegisterNearbyWorldBarrels()
+    if isServer() then
+        return
+    end
+
+    local player = getSpecificPlayer(0)
+    if not player then
+        return
+    end
+
+    local gmd = GetWPModData and GetWPModData() or nil
+    local cell = getCell and getCell() or nil
+    if not gmd or not cell or not WPIso or not WPIso.GetBarrel then
+        return
+    end
+
+    local px, py, pz = math.floor(player:getX()), math.floor(player:getY()), math.floor(player:getZ())
+    local radius = 22
+    local zMin = math.max(0, pz - 1)
+    local zMax = math.min(8, pz + 3)
+
+    local missing = {}
+    for z = zMin, zMax do
+        for y = py - radius, py + radius do
+            for x = px - radius, px + radius do
+                local sq = cell:getGridSquare(x, y, z)
+                if sq then
+                    local isoBarrel = WPIso.GetBarrel(sq)
+                    if isoBarrel then
+                        local id = WPUtils.Coords2Id(x, y, z)
+                        local barrelNode = gmd.Barrels and gmd.Barrels[id] or nil
+                        if not barrelNode then
+                            addDebugTile(missing, x, y, z, "M")
+
+                            local _, wmax = WPIso.GetWaterStatus(isoBarrel)
+                            local bid = WPIso.GetBuildingBid and WPIso.GetBuildingBid(sq) or nil
+                            if (not bid or bid == "") then
+                                bid = findNearbyLinkedBid(sq, 4, 2)
+                            end
+                            if WPVirtual and WPVirtual.BarrelAdd then
+                                WPVirtual.BarrelAdd(x, y, z, (wmax or 40) * 100, bid)
+                            end
+                        end
+                    end
+                end
+            end
+        end
+    end
+
+    Patch.debugOverlay.missingWorld = missing
+end
+
+local function relinkUnboundBarrels()
+    if isServer() then
+        return
+    end
+
+    local player = getSpecificPlayer(0)
+    if not player then
+        return
+    end
+
+    local gmd = GetWPModData and GetWPModData() or nil
+    if not gmd or not gmd.Barrels then
+        return
+    end
+
+    local cell = getCell and getCell() or nil
+    if not cell or not WPIso or not WPIso.GetBuildingBid then
+        return
+    end
+
+    for _, barrel in pairs(gmd.Barrels) do
+        local sq = cell:getGridSquare(barrel.x, barrel.y, barrel.z)
+        if sq then
+            local bid = WPIso.GetBuildingBid(sq)
+            if not bid or bid == "" then
+                bid = findNearbyLinkedBid(sq, 3, 2)
+            end
+
+            if bid and bid ~= barrel.bid and sendClientCommand then
+                barrel.bid = bid
+                sendClientCommand(player, "Commands", "BarrelMod", {
+                    x = barrel.x,
+                    y = barrel.y,
+                    z = barrel.z,
+                    bid = bid,
+                })
+            end
+        end
+    end
+
+    -- Also discover physical sinks/taps that never entered virtual data.
+    scanAndRegisterNearbyWorldBarrels()
+end
+
+local function recomputeDebugOverlay()
+    if isServer() then
+        return
+    end
+
+    local gmd = GetWPModData and GetWPModData() or nil
+    if not gmd or not gmd.Pumps then
+        Patch.debugOverlay.cache = {}
+        return
+    end
+
+    local out = {}
+    local unbound = {}
+    for _, pump in pairs(gmd.Pumps) do
+        table.insert(out, tracePumpNetwork(gmd, pump))
+    end
+    for _, barrel in pairs(gmd.Barrels or {}) do
+        if not barrel.bid or barrel.bid == "" then
+            addDebugTile(unbound, barrel.x, barrel.y, barrel.z, "U")
+        end
+    end
+
+    Patch.debugOverlay.cache = out
+    Patch.debugOverlay.unbound = unbound
+end
+
+local function drawTextSafe(x, y, text, r, g, b, a)
+    local tm = getTextManager and getTextManager() or nil
+    if not tm then
+        return
+    end
+
+    local ok = false
+    if UIFont and tm.DrawString then
+        ok = pcall(function()
+            tm:DrawString(UIFont.Small, x, y, text, r, g, b, a)
+        end)
+    end
+
+    if not ok and tm.DrawString then
+        pcall(function()
+            tm:DrawString(x, y, text, r, g, b, a)
+        end)
+    end
+end
+
+local function drawTileSymbol(playerNum, tile, text, r, g, b, a)
+    local tx = isoToScreenX(playerNum, tile.x + 0.5, tile.y + 0.5, tile.z)
+    local ty = isoToScreenY(playerNum, tile.x + 0.5, tile.y + 0.5, tile.z)
+    drawTextSafe(tx, ty, text, r, g, b, a)
+end
+
+local function renderDebugOverlay()
+    if isServer() then
+        return
+    end
+
+    if not Patch.debugOverlay.enabled then
+        return
+    end
+
+    if not isIngameState() then
+        return
+    end
+
+    local player = getSpecificPlayer(0)
+    if not player then
+        return
+    end
+
+    Patch.debugOverlay.tick = Patch.debugOverlay.tick + 1
+    if Patch.debugOverlay.tick % Patch.debugOverlay.recomputeEveryTicks == 0 then
+        recomputeDebugOverlay()
+    end
+
+    local playerNum = player:getPlayerNum()
+    local px, py, pz = player:getX(), player:getY(), player:getZ()
+    local range = 55
+    local yLine = 186
+    local unboundCount = countEntries(Patch.debugOverlay.unbound or {})
+    local missingWorldCount = countEntries(Patch.debugOverlay.missingWorld or {})
+
+    drawTextSafe(20, 150, "[WP DEBUG] Pump grid overlay ON  (P pump, . pipe, B building node, T tap, R barrel, S sprinkler, X closed valve)", 0.8, 0.95, 1.0, 0.95)
+    drawTextSafe(20, 166, string.format("[WP DEBUG] Unbound taps (U): %d  (auto relink every 1 in-game minute)", unboundCount), 1.0, 0.45, 0.45, 0.95)
+    drawTextSafe(20, 182, string.format("[WP DEBUG] Missing virtual taps (M): %d  (physical object found, auto-registering)", missingWorldCount), 1.0, 0.65, 0.2, 0.95)
+
+    for _, traced in ipairs(Patch.debugOverlay.cache) do
+        local pump = traced.pump
+        local pActive = tostring(pump.active == true)
+        local pSource = pump.source and tostring(pump.source) or "none"
+        local summary = string.format("Pump %d,%d,%d active=%s source=%s pipes=%d targets=%d closedValves=%d",
+            pump.x, pump.y, pump.z, pActive, pSource, traced.pipeCount or 0, traced.targetCount or 0, traced.closedValveCount or 0)
+        drawTextSafe(20, yLine, summary, 0.6, 0.9, 1.0, 0.95)
+        yLine = yLine + 16
+
+        if math.abs(pump.x - px) <= range and math.abs(pump.y - py) <= range and math.abs(pump.z - pz) <= 4 then
+            drawTileSymbol(playerNum, {x = pump.x, y = pump.y, z = pump.z}, "P", 0.25, 0.65, 1.0, 1.0)
+        end
+
+        for _, tile in pairs(traced.pipes) do
+            if math.abs(tile.x - px) <= range and math.abs(tile.y - py) <= range and math.abs(tile.z - pz) <= 4 then
+                drawTileSymbol(playerNum, tile, ".", 0.35, 0.95, 1.0, 0.9)
+            end
+        end
+
+        for _, tile in pairs(traced.targets) do
+            if math.abs(tile.x - px) <= range and math.abs(tile.y - py) <= range and math.abs(tile.z - pz) <= 4 then
+                local symbol = tile.symbol or "T"
+                if symbol == "B" then
+                    drawTileSymbol(playerNum, tile, symbol, 1.0, 0.9, 0.2, 1.0)
+                elseif symbol == "S" then
+                    drawTileSymbol(playerNum, tile, symbol, 0.8, 0.9, 1.0, 1.0)
+                elseif symbol == "R" then
+                    drawTileSymbol(playerNum, tile, symbol, 0.95, 0.65, 1.0, 1.0)
+                else
+                    drawTileSymbol(playerNum, tile, symbol, 0.35, 1.0, 0.4, 1.0)
+                end
+            end
+        end
+
+        for _, tile in pairs(traced.closedValves) do
+            if math.abs(tile.x - px) <= range and math.abs(tile.y - py) <= range and math.abs(tile.z - pz) <= 4 then
+                drawTileSymbol(playerNum, tile, "X", 1.0, 0.25, 0.25, 1.0)
+            end
+        end
+    end
+
+    for _, tile in pairs(Patch.debugOverlay.unbound or {}) do
+        if math.abs(tile.x - px) <= range and math.abs(tile.y - py) <= range and math.abs(tile.z - pz) <= 4 then
+            drawTileSymbol(playerNum, tile, "U", 1.0, 0.2, 0.2, 1.0)
+        end
+    end
+
+    for _, tile in pairs(Patch.debugOverlay.missingWorld or {}) do
+        if math.abs(tile.x - px) <= range and math.abs(tile.y - py) <= range and math.abs(tile.z - pz) <= 4 then
+            drawTileSymbol(playerNum, tile, "M", 1.0, 0.7, 0.1, 1.0)
+        end
+    end
+end
+
+local function onPumpDebugToggle(_player, _context, _worldobjects, _test)
+    if isServer() then
+        return
+    end
+    if not isDebugModeEnabled() then
+        return
+    end
+
+    local fetch = ISWorldObjectContextMenu and ISWorldObjectContextMenu.fetchVars or nil
+    local square = fetch and fetch.clickedSquare or nil
+    if not square or not WPIso or not WPIso.GetPump then
+        return
+    end
+
+    local isoPump = WPIso.GetPump(square)
+    if not isoPump then
+        return
+    end
+
+    local context = _context
+    if not context then
+        return
+    end
+
+    local label
+    if Patch.debugOverlay.enabled then
+        label = "[WP DEBUG] Hide Pump Overlay"
+    else
+        label = "[WP DEBUG] Show Pump Overlay"
+    end
+
+    context:addOption(label, nil, function()
+        Patch.debugOverlay.enabled = not Patch.debugOverlay.enabled
+        if Patch.debugOverlay.enabled then
+            scanAndRegisterNearbyWorldBarrels()
+            recomputeDebugOverlay()
+        end
+    end)
+end
+
+if Events and Events.OnGameBoot then
+    Events.OnGameBoot.Add(tryApplyPatch)
+end
+if Events and Events.OnGameStart then
+    Events.OnGameStart.Add(tryApplyPatch)
+end
+if Events and Events.OnInitGlobalModData then
+    Events.OnInitGlobalModData.Add(tryApplyPatch)
+end
+if Events and Events.OnPreUIDraw then
+    Events.OnPreUIDraw.Add(renderDebugOverlay)
+end
+if Events and Events.OnPreFillWorldObjectContextMenu then
+    Events.OnPreFillWorldObjectContextMenu.Add(onPumpDebugToggle)
+end
+if Events and Events.EveryOneMinute then
+    Events.EveryOneMinute.Add(relinkUnboundBarrels)
+end
+
+tryApplyPatch()
diff --git a/42/mod.info b/42/mod.info
new file mode 100644
index 0000000..8db32a5
--- /dev/null
+++ b/42/mod.info
@@ -0,0 +1,6 @@
+name=Waterpipes B42 Patch
+id=hrsys_waterpipes_b42_patch
+description=Runtime compatibility patch for Waterpipes B42.13: player-constructed buildings + multi-level discovery (-1 to +3).
+author=Riggs0
+versionMin=42.13
+require=\Waterpipes
diff --git a/common/placeholder.txt b/common/placeholder.txt
new file mode 100644
index 0000000..e69de29