[injidup]

A 2d sketcher with constraints is kind of similar. For example the equation

A = B + C

Where A, B, C are the lengths of 3 parallel lines. Within the sketcher you can drag the length of any one of those lines and the other two will adjust to keep the constraints.

[fouronnes3]

Yes! I'd really like to make something graphical in this same idea space next. See g9.js for example, or parametric CAD software like FredCAD which kinda does what you said.