This version is for 1/8" thick acrylic, rather than 1/4", and half the height. A single 12"x12" stock will get you two complete nave sections, i.e. eight times the Gothy goodness of the original.

Isn't multiplication fun?

Because I didn't know what the kerf was, the tab/slot thickness was a little loose. A hot glue gun fixed that in a jiffy!

Nota Bene: The ladder-like pattern in the upper right corner is a kerf measurement pattern. You can remove it if you know, or don't want to know, your kerf.

The idea is to make several close cuts in the material, then stack the pieces and measure the material lost to the laser.