T hanks to Lillian Kemp for sharing this https://www.facebook.com/watch/?v=549215599326985
Project Recipe
2 pieces of 12"x12" DSP
Cut 3/4" off the top of each piece - save for handles.
Score on the 11-1/4" side @ 1-1/4", 10"
Score on the 12" side @ 1/2", 1-1/4", 2"