The picture with the wheels showing, is a side view. The pic with the board & the groove routed down the center, is a top view. The spool on the left, is the drive cord, which is fed up through bigger hole in the end of the grooved board, on the left end, facing you. The smaller spool, of red thread, is the binding cord itself, which is fed up through a small hole in the end of the groove, on the left side also, facing you. Small eyelets keep the drive cord separated a bit, so you have travel, as the speed of the travel is determined by the amount of space you have when the drive cord is double wrapped over the rod. The drive cord is reversed as in a Garrison style, to wrap the other direction. Both spools have tension devices on them, (springs with locking nuts) to set your tension, which this set up does NOT require much tension at all.