投球機

https://www.youtube.com/watch?v=h6uIkJL7J_4
https://www.youtube.com/watch?v=QAx1PT--NYY
https://www.youtube.com/watch?v=TKXgtOi_LFU
https://www.youtube.com/watch?v=MzffpZJTrTc
https://drive.google.com/file/d/1dBjpF82wTIDm6nSYVi_2zfeLEa7dAQh0/view
http://elesson.tc.edu.tw/md221/mod/forum/discuss.php?d=32

https://mangobot.blogspot.com/2016/11/blog-post_13.html