Give default value to z.

8By8/8By8.ino

@@ -476,6 +476,9 @@ void loop() {
                 z = round(result);
                 Cube::set_status(x, y, z, 3);
             }
+            else {
+                z = 0;
+            }
             Serial.print(x);
             Serial.print(" ");
             Serial.print(y);