diff --git a/assets/index.html b/assets/index.html
index 6bd7f4c..099c310 100644
--- a/assets/index.html
+++ b/assets/index.html
@@ -29,7 +29,7 @@
     function project(x, y, z) {
         var fov = 800;
         var scale = fov / (fov + z);
-        var isoX = (x - y) * 0.5;
+        var isoX = y - x;
         var isoY = ((x + y) * 0.5) - z;
         var sx = isoX * scale + W / 2;
         var sy = isoY * scale + H / 2;