diff --git a/tiny-engine/src/commonMain/kotlin/com/github/minigdx/tiny/lua/MapLib.kt b/tiny-engine/src/commonMain/kotlin/com/github/minigdx/tiny/lua/MapLib.kt
index 592021c0..fdcfe715 100644
--- a/tiny-engine/src/commonMain/kotlin/com/github/minigdx/tiny/lua/MapLib.kt
+++ b/tiny-engine/src/commonMain/kotlin/com/github/minigdx/tiny/lua/MapLib.kt
@@ -127,7 +127,7 @@ class MapLib(private val resourceAccess: GameResourceAccess, private val spriteS
         }
 
         @TinyCall("Convert the cell coordinates from a table [cx,cy] into screen coordinates as a table [x,y].")
-        override fun call(arg: LuaValue): LuaValue = super.call(arg)
+        override fun call(@TinyArg("cell") arg: LuaValue): LuaValue = super.call(arg)
     }
 
     @TinyFunction(
@@ -151,25 +151,31 @@ class MapLib(private val resourceAccess: GameResourceAccess, private val spriteS
         }
 
         @TinyCall("Convert the coordinates from a table [x,y] into cell coordinates as a table [cx,cy].")
-        override fun call(arg: LuaValue) = super.call(arg)
+        override fun call(@TinyArg("coordinates") arg: LuaValue) = super.call(arg)
     }
 
     @TinyFunction("Get the flag from a tile.")
-    inner class flag : LibFunction() {
+    inner class flag : TwoArgFunction() {
 
         @TinyCall("Get the flag from the tile at the coordinate cx,cy.")
-        override fun call(@TinyArg("cx") a: LuaValue, @TinyArg("cy") b: LuaValue): LuaValue {
-            val tileX = a.checkint()
-            val tileY = b.checkint()
+        override fun call(@TinyArg("cx") arg1: LuaValue, @TinyArg("cy") arg2: LuaValue): LuaValue {
+            val (tileX, tileY) = if (arg1.istable()) {
+                arg1["cx"].toint() to arg1["cy"].toint()
+            } else {
+                arg1.checkint() to arg2.checkint()
+            }
 
-            val layer = resourceAccess.level(currentLevel)?.intLayers?.first { l -> l != null } ?: return NONE
+            val layer = resourceAccess.level(currentLevel)?.intLayers?.first { l -> l != null } ?: return NIL
 
             return if (tileX in 0 until layer.width && tileY in 0 until layer.height) {
                 valueOf(layer.ints.getOne(tileX, tileY))
             } else {
-                NONE
+                NIL
             }
         }
+
+        @TinyCall("Get the flag from the tile at the coordinate table [cx,cy].")
+        override fun call(@TinyArg("cell") arg: LuaValue): LuaValue = super.call(arg)
     }
 
     @TinyFunction(
diff --git a/tiny-engine/src/commonMain/kotlin/com/github/minigdx/tiny/lua/MathLib.kt b/tiny-engine/src/commonMain/kotlin/com/github/minigdx/tiny/lua/MathLib.kt
index bacbd239..9254fc2a 100644
--- a/tiny-engine/src/commonMain/kotlin/com/github/minigdx/tiny/lua/MathLib.kt
+++ b/tiny-engine/src/commonMain/kotlin/com/github/minigdx/tiny/lua/MathLib.kt
@@ -31,6 +31,7 @@ class MathLib : org.luaj.vm2.lib.MathLib() {
         math["dst"] = dst()
         math["dst2"] = dst2()
         math["sign"] = sign()
+        math["roverlap"] = roverlap()
         math["perlin"] = perlin(Random.nextLong())
         return math
     }
@@ -146,6 +147,27 @@ class MathLib : org.luaj.vm2.lib.MathLib() {
         }
     }
 
+    @TinyFunction("Check if two (r)ectangles overlaps.")
+    inner class roverlap() : TwoArgFunction() {
+        @TinyCall("Check if the rectangle rect1 overlaps with the rectangle rect2.")
+        override fun call(
+            @TinyArg("rect1", "Rectangle as a table {x, y, with, height}.") arg1: LuaValue,
+            @TinyArg("rect2", "Rectangle as a table {x, y, with, height}.") arg2: LuaValue,
+        ): LuaValue {
+            val ax = arg1["x"].toint()
+            val ay = arg1["y"].toint()
+            val awidth = arg1["width"].toint()
+            val aheight = arg1["height"].toint()
+
+            val bx = arg2["x"].toint()
+            val by = arg2["y"].toint()
+            val bwidth = arg2["width"].toint()
+            val bheight = arg2["height"].toint()
+
+            return valueOf(ax < bx + bwidth && ax + awidth > bx && ay < by + bheight && ay + aheight > by)
+        }
+    }
+
     @TinyFunction("Perlin noise. The random generated value is between 0 and 1.")
     inner class perlin(seed: Long) : ThreeArgFunction() {