diff --git a/src/net/torvald/terrarum/gameworld/GameWorld.kt b/src/net/torvald/terrarum/gameworld/GameWorld.kt
index 69e95190c..f6b1b1d21 100644
--- a/src/net/torvald/terrarum/gameworld/GameWorld.kt
+++ b/src/net/torvald/terrarum/gameworld/GameWorld.kt
@@ -428,14 +428,14 @@ open class GameWorld : Disposable {
         wiringGraph[blockAddr]!![itemID]!!.recvStates.add(state)
     }
 
-    fun getAllWiringGraph(x: Int, y: Int): Iterable<Map.Entry<ItemID, WiringSimCell>>? {
+    fun getAllWiringGraph(x: Int, y: Int): HashMap<ItemID, WiringSimCell>? {
         val (x, y) = coerceXY(x, y)
         val blockAddr = LandUtil.getBlockAddr(this, x, y)
         return getAllWiringGraphUnsafe(blockAddr)
     }
 
-    fun getAllWiringGraphUnsafe(blockAddr: BlockAddress): Iterable<Map.Entry<ItemID, WiringSimCell>>? {
-        return wiringGraph[blockAddr]?.asIterable()
+    fun getAllWiringGraphUnsafe(blockAddr: BlockAddress): HashMap<ItemID, WiringSimCell>? {
+        return wiringGraph[blockAddr]
     }
 
     fun clearAllWireRecvStateUnsafe(blockAddr: BlockAddress) {
diff --git a/src/net/torvald/terrarum/gameworld/WorldSimulator.kt b/src/net/torvald/terrarum/gameworld/WorldSimulator.kt
index 7bcfcaa1b..370430398 100644
--- a/src/net/torvald/terrarum/gameworld/WorldSimulator.kt
+++ b/src/net/torvald/terrarum/gameworld/WorldSimulator.kt
@@ -6,9 +6,11 @@ import net.torvald.terrarum.TerrarumAppConfiguration.TILE_SIZE
 import net.torvald.terrarum.blockproperties.Block
 import net.torvald.terrarum.blockproperties.BlockCodex
 import net.torvald.terrarum.blockproperties.Fluid
+import net.torvald.terrarum.blockproperties.WireCodex
 import net.torvald.terrarum.gameactors.ActorWithBody
 import net.torvald.terrarum.gamecontroller.KeyToggler
 import net.torvald.terrarum.gameitem.ItemID
+import net.torvald.terrarum.itemproperties.ItemCodex
 import net.torvald.terrarum.modulebasegame.TerrarumIngame.Companion.inUpdateRange
 import net.torvald.terrarum.modulebasegame.gameactors.ActorHumanoid
 import net.torvald.terrarum.modulebasegame.gameactors.BlockBoxIndex
@@ -478,11 +480,28 @@ object WorldSimulator {
         fixture.worldBlockPos?.let {
             val branchesVisited = ArrayList<Point2i>()
             val branchingStack = Stack<Point2i>()
-            val startPoint = it + fixture.blockBoxIndexToPoint2i(bbi)
-            branchingStack.push(startPoint)
+            val point = it + fixture.blockBoxIndexToPoint2i(bbi)
+            branchingStack.push(point.copy())
 
             while (branchingStack.isNotEmpty()) {
-                
+                // get all wires that matches 'accepts' (such as Red/Green/Blue wire) and propagate signal for each of them
+                world.getAllWiresFrom(point.x, point.y)?.filter { WireCodex[it].accepts == wireType }?.forEach { wire ->
+                    world.getAllWiringGraph(point.x, point.y)?.get(wire)?.let { node ->
+                        val connexion = node.con.toInt()
+                        when (wireConToStatus[connexion]) {
+                            WireConStatus.THRU -> {
+                                // TODO
+                            }
+                            WireConStatus.END    -> {
+                                // TODO
+                            }
+                            WireConStatus.BRANCH -> {
+                                // TODO
+                                branchingStack.push(point.copy())
+                            }
+                        }
+                    }
+                }
             }
         }
     }