1. anyinstructionthatworksfirstone wayand thenthe other
2. ahingedswitchthatcanassumeeitheroftwopositions
3. afastenerconsistingofapegorpinorcrosspiecethat isinsertedintoaneyeat the end ofaropeorachainoracablein order tofastenittosomething (asanotherropeorchainorcable)