cor_d = [(corners[0], (c[0] - corners[0][0], c[1] - corners[0][1]), c) for c in
corners[1:]]
cor_d = [(float(a[0] * b[0] + a[1] * b[1]) / (sqrt(a[0] ** 2 + a[1] ** 2) *
cor_d = [(corners[0], (c[0] - corners[0][0], c[1] - corners[0][1]), c) for c in
corners[1:]]
cor_d = [(float(a[0] * b[0] + a[1] * b[1]) / (sqrt(a[0] ** 2 + a[1] ** 2) *