We used that in school when I was a kid. Gelatin in a cookie sheet, then indelible pencil to make original, soak original on gelatin tray wet it down. After indelible pencil soaks into the gelatin begin copies by placing paper on gelatin and wet it down. Remove copy and hang to dry.
Those were the days. Unless you got suckered on the Super Secret spy telescope with a secret code sender ring, you haven't lived.
LOL, no I haven’t lived evidently.
I think we got the gheto version of that in my school.
It was a very small school, and it was about 8.5 x 11.
I know what you mean.
Those could be cool even today, and it would seem a relatively simple DYI project.