u sing a 6 x 6 piece of dsp , cut up to put on 3 cards
Project Recipe
First cut at 3 inches
Using that piece cut (2) 1" x 3" pieces you should have 3 x 4 piece left.
Cut this diagonally.
On your next 3 x 6 piece, cut off I inch ( 1 x 3)
then cut (3) at 1 1/2 inches ( 1 1/2 x 3 )
That leaves you with a 1/2 x 3 piece not used
You should have something like this