Made this at Techshop.ws
You will need:
Plank of wood
Some wood cutting tools -- I used the vertical band saw
A few images with a common theme
Step 1: Create your coasters on Illustrator and laser the images
4in by 4in is a good size
Design your coasters however you like. Would be good to stick with a theme here.
Download my .ai file in the attached section if you'd like to use it.
For rastering - 75 speed/ 90 power