@6212 the nature of this pattern leads to wavier edges if knotted exactly according to the pattern, however, the edges can be made a little bit straighter if you make all the knots on the left side forward backward knots, and all the knots on the right side backward forward knots. this can be done without changing the color of any of the knots because the only two knots on each side that aren't forward-backward or backward-forward are same string knots. I hope this helps!
Just a word of advice make the 2nd, 3rd, and 4th blue strings much longer than the rest since they get used more in the pattern and will end up really short fast.
