I understand what a Luohan is in the Buddhist doctrinal sense, but how does the term fit into Shaolin Kung Fu movement? What makes the form Luohan? I've seen three Luohan forms (short, xiao, and da), learned the xiao luohan, but I'm missing what makes it Luohan. What are the concepts involved? What are the signature movement(s) involved? (zuo pan?) Is it just empty-hand forms or are there Luohan weapons forms?