What better use of the computer controlled x y motors of a 3D printer than to give yourself a tattoo.  Tattooing straight lines and perfect circles are super hard so the enigmatic crew of Appropriate Audiences have solved that problem by attaching a tattoo machine to their 3D printer to give the perfect circle tattoo (not the band logo).

3d print a tattoo

This should be listed under ‘do not try this at home’ as many territories have different laws on who and how to you can get tattooed.  To follow their process so you can see exactly how not to try this at home, Pierre Emm and friends have shared their how (not) to on Instructables.