I used k2tog, k1, SSK in the middle of the right side rows instead of a double central decrease to get a bold diagonal line through the middle of the domino block. I cast on 51 stitches but you can cast on any large odd number of stitches to begin. There are 2 pattern rows. Any combination of yarn and needles will work. This simple block knits up fast!
The block pictured is 5.5” square.

Skills needed: cast on, knit, k2tog, SSK, purl, p2tog and k3tog.

Gauge is not important in this pattern. Any block-able yarn/thread will work. Make a swatch to check gauge and appearance.

36 yards of Lion Brand 24/7 yarn will make a 51-stitch Big Diagonal Domino block at gauge.