Units are 'P' or 'J' shaped. must alternate P and J cells Vertical Lanes can go Up or Down as desired Each cell will be all same letter and direction. eg. P6v uses 3 P down units, nests with J6v Build cells and nest together, should be no gaps. Build Left and RIght edges, right can be exterior or interior w Ctrl+shift 3 Horizontal lanes start lower left, end upper right. Each cell's vertical lane run as built.