See BP1061 for a version of this with only squares and which allows infinite nesting.
See BP71 for a Problem about counting levels of nesting.
Adjacent-numbered pages: BP1017 BP1018 BP1019 BP1020 BP1021  *  BP1023 BP1024 BP1025 BP1026 BP1027
easy, nice, precise, allsorted, traditional
varied_thickness_curves_drawing [smaller | same | bigger]
Aaron David Fairbanks