Step 1: Make rainbow wood
Follow the steps in this Rainbow Wood Instructable and make up some stock material.
You can also skip this step and use any kind of hard wood that you like.
Take your stock material and slice a piece off in the table saw using a crosscut sled. The width of your cut will equal the width of your chopstick rest. I cut off around 1 1/8".
The thickness of the rest is determined by the thickness of the stock. The length of the rest will be determined by another cut that comes later.