Reduction printing is so simple, yet it is one of the hardest things to explain (second to Pokémon Go!). One thing that is hard to explain to people is the "why." You roll out a full block of color only to have a small area show. What a waste, right?
I disagree. Each layer is a foundation. Each layer can move you to improvisation. See the lettering? I was inspired by seeing the flat expanse of beige I had printed. The tire in the trunk was also a last minute add.
This is color #7, with 5 to go.