Haniwa Stamp

"Haniwa" is Japanese clay figures made in 3rd to 6th centuries AD.
https://en.wikipedia.org/wiki/Haniwa

Especially we used the one below as reference.
http://www.tnm.jp/uploads/r_collection/LL_32.jpg

They are actually stamp body and express "OK" and "ReTake (not OK)" by both their look and stamp itself.

The stamp parts are exchangeable by pin.

A school project with Miss Kajiwara.

Also, you can buy finished product from here (Japan only, sorry).
https://minne.com/items/2343887