The first sketch had an invention too. I haven't read about it or seen it done, but I'm sure it must be used routinely by artists for roughs, it's so useful and quick and effective. The sketch was done with markers (Faber Castell Pitt pens) which are strongly coloured. To lighten the background I glued on tracing paper which worked well.
|Forest sketch, markers on paper 9 x 12"|
At the same time, I've gained confidence in my ability to invent and now realize I do it all the time without remarking on it even to myself. It's a matter of bringing unconscious things into consciousness which might not always be a good thing? Besides, I doubt any of these are new, they're things that happen naturally. You encounter some sort of obstacle when making work and look around the environment for a way around it. I bet if I googled any of these I'd get pages of results.