In certain zones (Z5, Z6, and Z7), no impermanent obstructions existed because the line in the zone is a path to the exitSoufstatihnaebilcitaym201p7,u9s, 2.2O85n the other hand, the most common impermanent obstruction1s1wof e16re in Z1. The most freMqeuaennwthiimle,pimerpmeramna...