+----------------------------+
/ \
/ +----+----+ \ / /x \ / / + \
| / | | +----+----+----+ | | | | | | | | +----+----+----+ | | | | \ +----+----+----+----+ / \ | | / \ S----+----+ / \ | / +--------------+-------------+ | + | + x 1
+----------------------------+
/ \
/ +----+----+ \ / /x \ / / + \
| / | | +----+----+----+ | | | | | | | | +----+----+----+ | | | | \ +----+----+----+----+ / \ | | / \ S----+----+ / \ | / +--------------+-------------+ | + | + x 1