@Writer233 It is a gradient yarn. You can buy the yarn already made in yarn stores. Or you can do it yourself, in fact there is a tutorial here on braceletbook that can help you, it's called "How to Make Multicolored Thread" by KrazyKnotz in the tutorial session in the banner above. I hope to be helpful 🌷 (sorry for my English)
O so cute 😍 yesterday in class, I was trying to draw some tessellating cats on graph paper, but your solution looks so much better than what I came up with!
gunch
