...

example/src/main.nub

@@ -28,6 +28,16 @@ extern "main" func main(args: []cstring): i64
         }
         raylib::EndDrawing()
 
+        if x + width > raylib::GetScreenWidth()
+        {
+            direction.x = -direction.x
+        }
+
+        if y + height > raylib::GetScreenHeight()
+        {
+            direction.y = -direction.y
+        }
+
         x = x + @floatToInt(i32, direction.x)
         y = y + @floatToInt(i32, direction.y)
     }