Physarum trails guide

Start

The tool opens with two sample pictures, A and B, and the Capillaries preset. A network starts growing at once while picture A fades into picture B. The picture fills the frame; the panel sits beside it.

What you need

• A current browser with WebGL 2. Chrome, Edge, Firefox and Safari all have it.
• Two pictures of your own, if you want them. Any image the browser can open works; the samples are there until you swap them.

Your first result

1. Open Physarum trails and watch the gold threads gather on the bright parts of the picture as it turns from A into B.
2. Press Replay at the top of the panel. The trail clears and the network grows again from an even scatter of agents, starting from picture A.
3. Press a preset under Presets, such as Crimson web, then press Replay: the new network grows while picture A turns into picture B.
4. Tap the picture. The agents inside a small circle round the tap are scattered afresh inside it. See reseed.
5. At the top of the panel, press the Image A and Image B tiles to pick your own two pictures, or drop two at once. Press Save PNG for a still, or Record video to keep one run.

Good to know

• Every preset keeps A → B transition on. Turn it off under Sliders to keep to picture A.
• Moving any control takes the highlight off the preset. Most controls change the network while it grows; press Replay to see a whole run with your settings.
• The frame takes the shape of picture A. Picture B is stretched to that shape, so two pictures of the same shape look best.
• On a phone the controls sit in a bar at the bottom of the screen. Tap the bar to open them.