Flock

get them in. don't rush them.

drag a dog to pen sheep off a mountain road -- walk them and they flow, rush them and they scatter

Each animal keeps a flight zone: step in calmly and it moves away, step in fast or deep and it bolts. Standing against its shoulder decides which way it turns. Calm edge pressure moves the flock; a rush scatters it.

Concepts: emergence, biology, feedback-loops.

An interactive you play with one thumb, on Wundr.