Concentric Shower Knobs

I have a shower with odd concentric knobs -- one to turn the water on and off, one for the temperature -- which wore out and were non-functional. I couldn't find a replacement, so I took measurements from the valve stems and old knobs to make these.

Printed in PETG to stand up to use by two teenagers -- red was what I had on hand.

No support for the On/Off knob, support required for the Hot/Cold knob.