In the 3D-view on the right you can see a prism shaped basic cell. Two upright sides are full walls. The other two are standing arcs.[br]Left you can see the top view as a square. Working with colors and vectors you can clarify in the 2D view how the cell looks like in 3D:[br][list][*]Green means that you can follow a side of the cell along a horizontal edge.[/*][*]Red means a standing arc.[/*][*]Using graphs in cells and constructions you can follow the construction from bottom to top. The color indicates if you're moving just horizontally or vertically as well.[/*][/list]