Remixed SonjaSelena's model as I wanted mine to last longer, and the springy/gap design looked like it might snap easily. Added a simple round 'coin' back, so that it's a solid object, with the sickness shape sticking out of it.

I don't have an AMS, but I just add a pause on my A1 Mini and change the filament manually to get a 2-colour thing going on.

Personally use the Arachne wall generator on these to fill the gaps better, with an 0.12 layer height and nice slow (50mms) outer walls and top surface. I'm going to try hilbert curve on the main coin flat surface next.