More-power-from-truckers-hitch-zrig-from-dual-input-of-1-person using own Equal &amp; Opposite force autonomously w/o any other effort expended.  Just alike had someone else helping exert force into the system with you, but not at your input point,  and must be in opposite direction.  In a typical 3/1 compression/tightening Trucker's Hitch, also known as a Zrig, this can give 4xEffort , plus not shown 3xBodyweight if hanging on end D.  Usually the lift on the lower anchor would be getting 2xEffort input can also be used for lifting; but with the dual input B+D it is 4x like the top compression pull, but only adds 2xBodyweight if that is put into the mix...
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