diff --git a/index.html b/index.html
index 64be082e..0c565e9e 100644
--- a/index.html
+++ b/index.html
@@ -13048,6 +13048,10 @@ onAddElementList = [];
 function onAddElement(callback) {
 	onAddElementList.push(callback);
 }
+validateMovesList = [];
+function validateMoves(callback) {
+	validateMovesList.push(callback);
+}
 canvasLayers = {
 	// bg: document.createElement("canvas"),
 	pixels: document.createElement("canvas"),
@@ -13764,6 +13768,16 @@ function langKey(key,fallback,template) {
 		function tryMove(pixel,nx,ny,leaveBehind,force) {
 			if (pixel.drag && force !== true) { return true; }
 			if (pixel.del) { return false }
+			if (validateMovesList.length !== 0 && force !== true) {
+				for (let i = 0; i < validateMovesList.length; i++) {
+					const result = validateMovesList[i](pixel,nx,ny);
+					if (result === false) return false;
+					else if (Array.isArray(result)) {
+						nx = result[0];
+						ny = result[1];
+					}
+				}
+			}
 			var info = elements[pixel.element];
 			var oob = outOfBounds(nx,ny);
 			if (isEmpty(nx,ny,false,oob)) { // If coords is empty, move to coords
diff --git a/mods/gravity_test.js b/mods/gravity_test.js
new file mode 100644
index 00000000..3c90a653
--- /dev/null
+++ b/mods/gravity_test.js
@@ -0,0 +1,51 @@
+// validateMoves((pixel,nx,ny) => {
+//     if (pixel.y-ny < 0) { //goes down usually
+//         return false;
+//     }
+// })
+
+validateMoves((pixel,nx,ny) => {
+    if (elements[pixel.element].isGas) return true;
+    if (true || pixel.y-ny < 0) { //goes down usually
+        
+        nx = 0;
+        ny = 0;
+
+        const centerX = Math.floor(width/2);
+        const centerY = Math.floor(height/2);
+
+        let diffX = centerX-pixel.x;
+        let diffY = centerY-pixel.y;
+
+        let dirX = 0;
+        let dirY = 0;
+        if (Math.abs(diffX) > Math.abs(diffY)) {
+            dirX = Math.sign(diffX);
+        }
+        else {
+            dirY = Math.sign(diffY);
+        }
+
+        if (Math.random() < Math.abs(diffX)/100) diffX = Math.sign(diffX);
+        else diffX = 0;
+        if (Math.random() < Math.abs(diffY)/100) diffY = Math.sign(diffY);
+        else diffY = 0;
+
+        if ((diffX || diffY) && !isEmpty(pixel.x+diffX,pixel.y+diffY)) {
+            if (dirX !== 0) {
+                diffY = Math.random() < 0.5 ? 1 : -1;
+            }
+            else if (dirY !== 0) {
+                diffX = Math.random() < 0.5 ? 1 : -1;
+            }
+        }
+
+        // if (!(pixel.y-ny)) {
+        //     diffX += pixel.y-ny;
+        //     diffY += pixel.x-nx;
+        // }
+
+        return [pixel.x+diffX,pixel.y+diffY];
+
+    }
+})
\ No newline at end of file