patternshop: a layered drawing (compositing) for Decker

what is decker? see here: https://internet-janitor.itch.io/decker/community and here:  http://beyondloom.com/decker 

for my other decker things see: https://codeberg.org/woodring/

It's a module and several contraptions that emulate layered drawing in other drawing tools. Or, it can be thought of as "Decker mega-underpaint mode."

reload if video is not playing:

1. make at least three cards

2. put the patternshop contraption on each of those cards.

3. switch to interactive mode.

4. press 0 (zero) on each of the cards to activate the contraption.

5. draw on the first card in interactive mode.

6. switch to the second card. what was drawn on the first card appears there.

7. draw on the second card.

8. switch to the third card. what was drawn on the second will be under the first.

9. et voila, layered drawing!

Why is this important? Imagine:

• card1 has a rough sketch.

• card2 shows card1, to trace over card1's sketch.

• card1 is deactivated, automatically removing the sketch, without having to manually erase it from card2.

• card3 shows the outline of card2, to add shading without worrying about staying exactly in the lines.

For a more detailed README, see:  https://codeberg.org/woodring/decker.patternshop