A simple fillet radius gauge (1 to 10mm) you can have on you at-all-times. Especially useful for those emergencies when you're making a 3D-model and you need the exact fillet size in seconds.
I've printed the model with 0.15 layer height and the uploaded GCODE has a filament change pause right before the numbers so you can switch to another color filament.
The author marked this model as their own original creation.