This project is for a 65x65 round magnet (or coaster if you scale it up) for Stillson from the movie The Dead Zone.   Possibly a silent protest item if you can't do so in the open.  

Project includes the 3mf with the colors presliced and uses a .2 nozzle for detail.   Underneath are 2 indents for 15mm X 1mm magnets if you want to add them to complete the magnet - else this could be redone in Bambu and have those negative areas removed if scaling up for a coaster.  

There are only 7 filament changes here similar to a Hueforge but this is just based on an SVG with the layers raised slightly to accommodate the coloring.   Colors will vary based on your greys and whites.  I didn't have a light enough grey so i used the Bambu Marble White PLA.

Enjoy.

Layer Color swaps based on .10 layer height
33 red
32 white
30 blue
27 white
26 light grey
24 dark grey
21 black
0 white