All left-sorted examples have 2^n distinct white regions (counting the background), where n is the number of shapes in the image.
https://en.wikipedia.org/wiki/Venn_diagram
Similar solution to BP1262, except there overlaps do not have to be unique.
Adjacent-numbered pages: BP1256 BP1257 BP1258 BP1259 BP1260  *  BP1262 BP1263 BP1264 BP1265 BP1266
notso, left-narrow, left-null, perfect
Leo Crabbe