objective markers
thingiverse
Objective Markers: I Have Used Dices From Unbalanced Dices By RandomGuy (https://www.thingiverse.com/thing:123456)
Download Model from thingiverse
With this file you will be able to print objective markers with your 3D printer. Click on the button and save the file on your computer to work, edit or customize your design. You can also find more 3D designs for printers on objective markers.