Did Letraset invent the process of rub on letters, or get it from elsewhere? Because I think before I knew about the letter, in the late sixties I was given some sets of animal rubons that worked the same way, but I can’t remember if they were branded “Letraset”. Thise were great fun, animal artwork that you could place where you liked, without needing to be an artist.
I never did much with actual letters, but in the eighties one coukd get rub-on traces for laying out printed circuit boards. Rub them on, and it would act as resist when you put the copper circuit board in etchant to dussolve the copper where you didn’t want it.
This really was “revolutionary”.