Summary

"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

Instructions

I am using DaVinci 1.0 3D printer by XYZ printing.

Layer pitch is 0.3mm.
Normal speed and normal shell thickness.

No raft. No support.
With stick paste(Tombow, Shiwanashi PIT).

200 minutes to print. 30 minutes for shaping, constructing and sanding.
20m for ABS.

Other parts,
2 pins (ø3*10, SUS)

How to use pins?
https://www.youtube.com/watch?v=BNg1lNYXcFk

In case of traditional machining, making accurate pin-holes on object is not so easy thing,
especially if the object is small, has irregular shape or the pin-hole is angled.
Because it needs additional assembling jigs to fix.

However, in case of 3D printing, it is pretty easy.
It does not need any other cost, except adding holes in 3D data.

The metal pins are enough accurate, so you can make both type of holes lock and roose easily.
Also it is much more strong than 3D printing materials, so you can make thin strut or axle.
Also it is enough cheap so you can bury under objects, or glue it.

Of course you can use screws. Actually screws are more usual in real world.
However you have to tap holes, you can not make loose screw or you can not joint objects face by face because it needs driver.

note. You need "reamer" and "drill chuck" to adjust holes.

Haniwa Stamp