Prusa i3 Mk2 Ergonomic Control Knob

I wanted a better knob for the control panel on my Prusa i3 MK2, but none that I found on Thingiverse were quite what I wanted. I designed this version with two main advantages over others. First, it has a four-point star shape that comfortably accommodates your right thumb for navigation without looking away from the screen (with a recessed center area for clicking the current selection). And second, the back side has a flexible socket patterned after the original Prusa knob, which makes instal