What is pmm1 and pmm2?

What is PMM 1 why it is impossible?

WHAT IS PMM-1 A PMM1 is a Thermodynamic system that undergoes a cyclic process that produce no external affects other than the rise ( or fall) of a weight in a gravity field. WHY IS IT IMPOSSIBLE? PMM-1 state that work can still be produce in a cyclic process. This definition is against first law of thermodynamics and conservation of energy. According to first law of thermodynamics, in cyclic process E2- E1 = mg (h2 - h1) h2= h1 in cyclic process so the above equation yields E2=E1. where as according to PMM-1 you can produce work even when energy is zero (0), which makes it impossible