Threw this together as a remix from heinandres case design
I recommend a filament change after the 1st layer, so the design on the bottom pops out more.
Make sure to disable brims/supports and such to prevent your slicer from sneaking pesky unwanted filament into the pattern. Print on a glass bed to get a glossy clean finish on the back :)

Custom i3

No

No

0.15

10