This is a Steve Good pattern. The original was somewhat larger ( 7 inches ), but I need to use up some 3 1/2" cork coasters I have. So, I reduced the pattern until it just fit within the 3 1/2" coaster. I cut the inside of the pattern, then laminated the wood to the cork, and after the glue (polyurethane, 100% waterproof) cured I cut the outside. Everything worked like a charm, very pleased with the result ( many, many times it just doesn't work the way I want and I have to make adjustments).
1/4 inch Elm, 1/8 inch cork, FD Polar #1 for the inside, #3 for the outside.