This box can be stacked by printing multiple copies.
Copic Ciao storage 36 Slots.
The hole size is 14mm in diameter and 120mm deep.
Pens smaller than 14mm in diameter can be used.
It can be used either standing up or lying down.
I would be happy if you could upload it on SNS etc.
Copic Ciao 36 color → https://amzn.to/3v7FvKe
72 color → https://amzn.to/3P6HfKI