Collage Kit

A few things I forgot to mention in the video:

- I meant to point out that the canvas can be a posterboard instead of the table, so after you arrange your tags, you can tape them down to make a permanent "machine" for that particular geometry.  It doesn't have to be ephemeral!

- One thing I was trying to explore here was whether someone could make a Snowflake Maker without typing in vector math.  The replicators here have vector math, but you can imagine a world where dynamic geometry is specified more directly.  (That world might be Apparatus.)

- Scrubbable is rudimentary but handy. (I forgot to show scrubbing the threshold, where it's actually useful.)

local threshold = scrubbable(you, 0, 1) or 0.35   -- can be scrubbed between 0 or 1, defaults to 0.35

- Thanks Josh for both easy_persist and Postscript DSL!