A printable flexible coaster.
I've really admired Zomboe's chainmail, and printed quite a bit of it. However, I noticed that if a link twisted out of place, then the chainmail would "buckle" and it would be very difficult to fix.
I thought about it, and tried printing two layers of chainmail, one on top of the other. This would make the links completely closed loops, and prevent them from rotating. This worked great, except that the horizontal bridges for the two layers would stick together, so I hacked the code to add an offset to the bottom layer. Current versions should now print with no rework or wiggling necessary - the chainmail should be flexible.
An unexpected outcome was that the double layer chainmail displays some really interesting behavior. Try bending it up by holding opposite corners, and see what happens to the loose corners. Flip it and try it again.
Extra bonus: there is a module in there called bitchain() that helps you set up multicolor chainmail prints.
Make sure to print it at 0.27mm layer height. The model is built in exact multiples of this amount.
You can change this value in the OpenSCAD file if you want.
You can also try printing at larger sizes. It works well and is fun to play with.