I originally wanted to make a hexagonal variation on the Ultimate Coaster, but then decided to go with a heptagon. 
 

The model was quickly thrown together in FreeCAD.

Printing: select an interesting infill mode (pictures show hexagonal and Hilbert curve infill), adjust the amount of infill and remember to set solid layers on top and bottom to 0. 

Unless you want the hilbert curve but don't like how it's flapping in the breeze, a single bottom layer fixes that, but also gets rid of the nice color contrast – so adjust to your preference.

The included .3mf file uses Prusa Slicer object modifiers to allow everything to be printed in one go. Also, the “complete individual objects” option reduces stringing and prints faster because there's less travel.

PS: I enjoy the contrast between hexagonal infill, heptagonal coaster and octagon glass. It's a visual pun. Sorry not sorry. :)