heya; it's not difficult, really. for the twist: everything beyond the red end does NOT move, everything beyond the green end DOES. in between is the blend zone area. for the red/green Xs: everything between the red arms does NOT move, everything between the green arms DOES. in between is a blend zone. now, the x arms actually go off out into infinity, and if there is another body part between them, it might become affected by the bending, so you can curb the X's (and the twist bar) by using the spherical falloff zones. the trick to working with those is, throw the outer mat sphere far off to the side and just work with the inner mat sphere, at first. everything INside the green sphere DOES move. everything OUTside the red sphere does NOT move, unless it is also within the green sphere. (ie: the red sphere can overlap the green one, just as long as the edges fall where you want them.) everything between is a blend zone. also note: all children of the body part will move with it, regardless of the inclusion/exclusion zones.