-#define KH 32.0 // 32 s for a speed=1 rock to cross the screen horizontally.
-#define KV 24.0 // 24 s for a speed=1 rock to cross the screen vertically.
+#define KH (32.0*20) // 32 s for a speed=1 rock to cross the screen horizontally.
+#define KV (24.0*20) // 24 s for a speed=1 rock to cross the screen vertically.