划槳

https://docs.google.com/presentation/d/1gU-9AiMrtR0Y5sQMMxakzJFNUkkBDzgxAnukmIPRihI/edit?usp=share_link

 https://www.tinkercad.com/things/4bMEpgj3ac6-spectacular-hillar-jaagub/edit?sharecode=4ic0LQMEBMzi9GoxXhVmoZizKkXR9zlFEYtLbCIAEfE