"Typograms": typographic diagrams

interesting, maybe even useful, if having right fonts is not an issue

 google.github.io/typograms/

Typograms (typographic diagrams) is a lightweight image format (text/typogram) useful for defining simple diagrams in technical documentation.

Like markdown, typograms is heavily inspired by pre-existing conventions found in ASCII diagrams. A small set of primitives and rules to connect them is defined, which you can use to build larger diagrams.

Typograms optimizes for editability and portability (e.g. plain text is easy to maintain, change, store and transmit), at the cost of expressivity (e.g. SVG is more expressive) and ergonomics (e.g. higher level tools produce diagrams faster).