rainbow Rainbow
Draw a big rainbow across the sky
An easy rainbow drawing is just a few stacked arcs. Still, three arcs or seven, clouds at the ends or not, spanning the whole canvas or sitting small in the middle — two rainbows can hang in very different skies. The fun is discovering how big each of you thinks "big" is.
What the engine watches
A rainbow is stacked arcs, so the shape dimension looks at stroke count, proportions, symmetry and silhouette. Outer arc first or inner first, left-to-right or right-to-left, splits the stroke dimension, and clouds at the ends add a lot of strokes. A drawing built from several strokes. Compares stroke count, aspect ratio and symmetry; a single short line doesn't count. Whether you build a house from a triangle plus a square or draw it in one go decides everything.
How people usually draw it
The most common draws three or four big half-circle arcs from left to right, outermost first. Next come the seven-arc purists and the fluffy-clouds-at-both-ends camp. Most span the canvas, but some draw a small one in the middle or add a ground line below.
How to sync better
"Three arcs, outermost first, left to right, no clouds" syncs best. Spanning the canvas edge to edge also puts your placement and size with the majority. Agree on the number of arcs beforehand.
A little trivia
Counting seven colors in the rainbow goes back to Newton's Opticks (1704): he added indigo so the colors would match the seven notes of the musical scale. Other cultures count five or six.
FAQ
How many arcs do people usually draw?
Three or four is the majority; seven is rare. A mismatch maps straight onto the stroke count, so this is the one thing worth agreeing on first.
Should I draw clouds at the ends?
Most people don't. Clouds are bumpy loops that add strokes fast, and if only one of you draws them the silhouette changes too.