none in out
This type is applied to regular cellular structures only. When a structure is applied to a regular grid, it can be arranged in two distinct ways. First, it can be applied as a rectangular structure where positions in a two-dimensional grid are aligned at right angles to each other in each dimension such that minimal distance lines joining positions will form rectangles, e.g., in a vertically aligned cellular structure, any row in x will have an identical set of x values. The second structure is triangular in configuration such that minimal distance lines joining positions in the grid will form triangles. In the triangular structure, subsequent rows are offset from each other by one half the distance between consecutive positions in an alternating fashion. Consequently, the offset of alternating rows may be such that the first row starts at a position before the first position of the second row or the reverse may occur where the first row begins at a position after the start position of the second row. In the former case a choice of out is appropriate and for the latter case a choice of in is used. The value none is supplied for defining the offset of the rectangular case.