上課教材
http://blog.ilc.edu.tw/blog/blog/1279/trackbacks/637779
https://scratch.mit.edu/projects/129430302?fbclid=IwAR3PcxIER4GYgwl2HWTkjUwpUphiF_gWCkIFGJzq5FW_dC5UbgHV9ze_Gks
運轉的時鐘
https://ephrain.net/scratch-%E9%81%8B%E8%BD%89%E7%9A%84%E6%99%82%E9%90%98-running-clock/
