Hey, folks who understand alt text and limited vision accessibility:

I have need to write alt text for the diagram below. The alt text needs to be comprehensible to somebody who is encountering this kind of diagram for the ••very first time••. I could describe the images using the relevant jargon, but that would only serve people who already know the thing this activity is teaching them!

Any suggestions for how I could write good alt text for something like this? Is it possible? (The horizontal black bars are minus signs, i.e. subtraction. This is clear from context in the text, but probably not clear in the image.)

PLEASE NOTE: I am looking for people with ••relevant accessibility expertise••, not just random best shots from people who (like me) don’t really know much about this kind of problem.