Birds
Lined up
Paused
Tap = predator ยท drag = wall
How to play
- Watch: the birds start scattered. Within seconds they form flocks.
- Tap the sky to drop a predator. Drag to draw a wall.
- Turn on Show one bird's view, then play with the three rule sliders.
| Do this | Phone | Keyboard |
|---|---|---|
| Drop a predator | Tap the sky | Arrows, then Enter (on the sky) |
| Draw a wall | Drag on the sky | Arrows, then W (on the sky) |
| Remove predators + walls | Clear | C |
| Show one bird's view | The toggle | V |
| Play / Pause | Pause | P |
| Scatter the birds | Scatter | S |
What's happening?
- No bird is the leader, and none can see the whole flock. Each one only looks at birds inside its vision circle.
- Separation: "too close! move away."
- Alignment: "fly the same way as my neighbours."
- Cohesion: "don't get left behind: head for the middle of my neighbours."
- That's it. Nobody plans the flock. It emerges from lots of simple local rules, like real starlings, fish and ants.
- The lined up number shows it: 0% means every bird flies its own way, 100% means all one way.
Try this: turn Cohesion down to 0. What happens to the flocks? Now put it back and turn Alignment to 0 instead. Which rule makes a flock a flock?