[hyperman1]

The seti project sent such a message.

See https://en.m.wikipedia.org/wiki/Cosmic_Call which points to https://www.plover.com/misc/Dumas-Dutil/messages.pdf . Read annex B of that message.

We spent a night decoding it with minimal hints, which was reasonably easy. Basically, page 1 defines numbers as dots, binary and their own symbol set. Then they define math operations. This allows them to describe some physical and chemical relations, from which the metric system is derived. This allows them to create descriptions of physical thing which, combined with some crude graphics, let them tell about our home planet.

If that's possible, explaining qr codes should also be possible