add sch and src

software/pathTool/src/path/backward.py

@@ -0,0 +1,15 @@
+from collections import deque
+
+from lib import semicircle_generator
+from forward import g_steps, g_radius
+
+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)