Letter Stacking

I was thinking. About how we read left to right. The only reason we read left to right is because we were taught that way. Had we been born in China we would read top to bottom, right to left. But for that matter we might have been taught to read dark to light or front to back. Imagine how much page space you could save if we could just stack letters on top of one another. I don’t know if it would work. Maybe for short words like dog, but when I stacked ‘rendezvous’ it became unintelligible.