maybe it's too early, but i'm not seeing what you're saying ... can you show us what you are regarding as the side-adjacent unit squares on the first couple of iterations? jon -- inquiry list: http://stderr.org/pipermail/inquiry/ mwb: http://www.mywikibiz.com/Directory:Jon_Awbrey knol: http://knol.google.com/k/-/-/3fkwvf69kridz/1