These are the same cat with two different head styles. They were made from 3 mm MDF.
Update: May 9, 2018: The latest files incorporate the ability to choose between a 2.8 mm material thickness like cardboard from pizza boxes or 3 mm material like hardboard or Masonite. Assembly instructions have also been added.
If your laser cutter software does not support selection by line colour, consider trying https://github.com/LaserWeb/LaserWeb4 which I used to cut my cats.