This requires a multi-material printer. Use PrusaSlicer's smart fill tool to fill colors into the sections of the flag on the model. Print the coaster base with TPU.
Coasters featuring the flag of Puerto Rico. Size 3.75"
I sell sets of these at:
https://www.etsy.com/listing/1388898465/drink-coasters-puerto-rico-flag-set-of-4
The author marked this model as their own original creation.