Prepare yarn in a main color (MC) and an additional color (AC). Cast on the number of stitches divisible by 4 with MC.
R1(WS): purl all sts in MC
R2(RS): (k1 in AC, k3 in MC)x until the end of the row
R3(WS): purl all sts in MC
R4(RS): k2 in MC, (k1 in AC, k3 in MC)x until 2sts left to the end of the row, k1 in AC, k1 in MC
Repeat R1-4 the desired number of times.
Starting from R5, you can also just remember to knit each stitch of AC three stitches above the previous AC stitch. I use this approach in the video.