from collections import deque from lib import semicircle_generator g_steps = 20 g_radius = 25 def path_generator(): assert (g_steps % 4) == 0 halfsteps = int(g_steps/2) path = semicircle_generator(g_radius, g_steps, reverse=True) mir_path = deque(path) mir_path.rotate(halfsteps) return [path, mir_path, path, mir_path, path, mir_path, ], "shift", 20, (0, halfsteps)