Originally Posted by Jeanne S

Tapper, no special ruler. I started with 9" squares of each fabric, cut from 9"WOF strips. This was a large lap size (48" x 64" approx) so I used six 9" squares for each color row. Match up 3 squares with the bottom row color and 3 squares with the top row color. Sew diagonal seam and after cutting, Each 3 square pairs will yield 6 HST blocks for each row. The HST blocks finish out at approx 7 3/4" each. Hope that is clear. Easy to just add more HST blocks if you want it bigger.