D20 (20 sided dice) with additional braille numbers

A blind friend of mine likes to play pen and paper RPGs. He was searching for a D20 with braille numbers since ages. So I modeled and printed one. ;-)
## Revision history
- Version 1.5:
- celebrating, that this D20 got featured!
- sum of opposite numbers is always 21, now
- Version 1.4:
- rounded edges