I love gaming related coasters and found out no-one had made the Portal Warning Signs so decided to create them! :)
I've included all 12 of the designs.
When it comes to colouring the design, you can either paint the design, or print with multiple filaments!
If your printer can only print one colour (like mine) you can use Cura to pause mid print, I've written a short guide about how to do so here: https://sambrooks.net/mid-print-pausing-in-cura/
Coasters are a good size, but if wanting smaller coasters 80% scale works great!