The left-sorted patterns connect all four corners with a single black region. - Rhodri Prysor, Oct 16 2024
Adjacent-numbered pages: BP1247 BP1248 BP1249 BP1250 BP1251  *  BP1253 BP1254 BP1255 BP1256 BP1257
precise, allsorted, notso, blackwhite, right-null, bordercontent
Leo Crabbe