degree = 2;

xs = [1,  √2/2,  0, -√2/2, -1, -√2/2,  0,  √2/2,  1]
ys = [0,  √2/2,  1,  √2/2,  0, -√2/2, -1, -√2/2,  0]
ws = [1,  √2/2,  1,  √2/2,  1,  √2/2,  1,  √2/2,  1]

knots = [0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 4]