[] , [] , [^] , []Wiper / Wiper of bus(GC World : Various Problems ,Alternative of real thing)
This is a wiper of bus.
Let's move points.
What movement do you find?
Why does such movement occur?


Actual photograph
When shutting

A little opened

Opened widely

Looking from inside

Expansion a little

(Photographer:Yusaku Kanaya)

Forum of Geometric Constructor by Y.Iijima