Lutoslawski-style box notation

[mark]

Just wondered if anyone has a working solution to creating Lutoslawski-style box repeats such as this one: https://goo.gl/images/TYKdWt

I couldn't find a complete solution in either the LSR or mailing list archives. If not, I'll start putting together something probably based on the frame module from https://github.com/openlilylib/analysis, but any tips would be appreciated.

Thanks,

Mark