This was fun to knit! This pattern is worked with 2 needles and 2 yarn colors but a variegated yarn is worth considering, too. 3 double decreases are spaced an equal number of stitches apart and there is a decrease at the beginning of each row to make the 4th corner. A small seam is sewn in one corner to finish the square.
A large number of cast-on stitches will dwindle rapidly with all the decreasing. Cast on any multiple of 4 stitches + 11 stitches for the decreases.
Design idea: consider sewing together different sizes of squares for more visual interest. I found I needed more than twice the number of stitches to double the size of a Domino Box.

Skills needed: cast on, knit, SK2P, k2tog, gathering and securing remaining stitches. (No binding off.)

Gauge is not important in this pattern. Any yarn/thread will work. Make a swatch to check gauge and appearance. At my gauge, the 91-stitch, orange and white block is 4.75” square and the 51-stitch blue and white block is 2.75” square. The 91-stitch variegated Kroy Socks yarn block is 3.25” square.

About 7 yards of Lion Brand 24/7 yarn will make a 51-stitch Domino Box at gauge.