I've seen various iterations of the laser cut pencil cup on the web. Most are pretty similar. Here's mine. It's just a basic pencil cup with living hinges for the corners. It's set up to cut from 3mm birch. Mine was cut on a K40 eBay laser cutter. Friction seems to hold it together, but to be safe I'm going to use a dab of wood glue on the tabs. The tabs are a hair smaller than the slots to make the fit a little easier.
Edit: I should note that I made this kind of tall (6") because I use it for things like scissors and paint brushes and other taller than normal items.