Have you thought about a Recluce novel where two characters that can use a glass for far-seeing, send each other messages over a long distance by painted signs seen through the glass?

Actually, I’ve thought about it several times over the years, but decided that the “resolution” issue would make it too difficult to be practical. By resolution, I’m talking about the ability to see characters or symbols in a glass clearly… and that doesn’t even take into account lighting problems or whether mages could focus on the signs or paper. In the later of the forthcoming books about Alyiakal, however, I’ve addressed the “glass” communication issue/problem in a different way.