Just like `cases` environment, with a 2-line (or more) big curly brace to the left of some short equations - but I want to have 3 or 4 columns of equations across the page, each with left-brace.
So I can't have the brace outside the environment, I don't think, like the single-big-left-brace solutions I've seen with `aligned`/`array`/`cases` etc.
(Imagine 3 or 4 uses of 'cases' environment on a page, each with a large brace to the left of 2 or 3 short equations. What I want is like that, but with the cases/blocks 'stacked' horizontally instead of vertically.)

Sorry, if this has already been asked; I couldn't find it on here or online, and can't think how to do it. I just heard about `multicol`, maybe I'll have to use that, but it's surprising there seems no LaTeX/ams way of doing it. Thanks.

Edit: Ive been asked for an image. I tried without success, then I read that new users like me can't post them. Hopefully what I wrote is clear enough.