13, 9, 15, 11 in the diagram above. On the other hand, would mean the cells where is true and is false (that is, is true).

The grid is toroidally connected, which means that rectangular groups can wrap across the edges (see picture). Cells on the extreme right are actually 'adjacent' to those on the far left, in the sense that the corresponding input values only differ by one bit; similarly, so are those at the very top and those at the bottom. Therefore, can be a valid term--it includes cells 12 and