Some professional organisation defined these in, IIRC, the early 80s as similar to the more well known flow charts, but "structured". Instead of having arbitrary "goto" arrows, they had the equivalent of loops etc.

They were standardized, and I vaguely remember studying them briefly at O Level.

Of course they were about as useful as the well-known chocolate teapot, but I'd still like to be able to find a reference guide for them if possible - for roughly the same reason I was looking for a reference for standard Basic a while back.

Google tells me - well, nothing really. They may as well never have existed. Which is probably nearly (and perhaps completely) true - I certainly never heard of them anywhere else except when I was at school. There's a chance that they may even be my computer science teachers little joke.