This is a 3D ambigram that I made in TinkerCAD. You can see this in both front and back with one side saying "KEEP" and the other one saying "CALM". Supports are really important because otherwise you will only get the base with half formed letters and noodles on the side ;). By the way, the gcode. file is flavour Marlin.
The author marked this model as their own original creation.