Option 29: sumi-e ink. The bot is painted the Zen way. Its body is an ensō, a single-breath circle stroke that starts heavy and runs dry into streaks of "flying white." The eyes are two decisive dabs. A red seal is pressed at the end. Two more modes add an ink-wash landscape and 1960s-style ink-wash animation.

**A brush made of bristles.**
Each stroke uses 26 simulated hairs, each with its own ink supply. Outer hairs and heavy pressure use ink faster. When a hair runs low it skips, leaving white streaks (flying white, hihaku ). It's never programmed as a pattern; it emerges.

**Ensō bot:**
- One circle stroke that starts pressed and wet, then lifts and dries, leaving a gap. The ensō's gap is traditional: the circle is never "closed."
- Two eye dabs: press, pull diagonally, lift. The bot's slanted capsule eyes turn out to be classic brush marks.
- A light dry ground stroke, a pale wash for volume, and a red seal.
**Ink landscape:**
misty mountains in diluted ink, a bamboo stalk that pauses at each node, leaves pressed and flicked, a dry-brushed rock, and a small ensō bot sitting on it. Mist drifts across when it's finished.

**Ink-wash animation:**
the bot hops in soft grey washes with a partial dark contour and ink splashes on landing, redrawn 12 times a second. China's Shanghai Animation Film Studio pioneered this style in 1960 with Where Is Mama .

**Ink load 0.5, then Paint again.**
The circle breaks into dry streaks early, rough and energetic. At 1.6 it stays black and wet the whole way, with soft bleeding edges.

**Brush speed 2×.**
In real ink painting, speed changes the mark. Here it only changes playback time, a reminder that simulation separates what paper never could.

**Untick "Paper bleed."**
Edges go clean and vector-like. The soft halo is ink wicking along rice-paper fibres.

**Paint again several times.**
Every ensō is different: start angle, gap, wobble and ink supply vary. The tradition values that uniqueness.

**Sumi-e is decided in advance and executed once.**
There's no erasing. The animation shows the brush tip so you can feel the commitment of each stroke.

**The seal is part of the composition.**
Its red square balances the black mass, and placement is chosen as carefully as any stroke. This one uses an original glyph: a circle and two slashes, the bot.

**The mist is paper colour, not white.**
In ink painting, emptiness is the paper. Mist and sky are left unpainted rather than painted over.

**The bamboo pauses at nodes**
by briefly lifting the brush. The gap and slight blot say "joint" without drawing one.

**Bristle model**
```
brush cross-section: o o o o o o o o o o o o (26 hairs) ink per hair: █ █ █ █ █ █ █ █ █ █ █ █ start mid-stroke: ▓ █ █ █ █ █ █ █ █ █ █ ▓ outer hairs drain faster end of stroke: ░ ▓ █ ▓ ▓ █ ▓ ░ ░ skips → flying white
```

**Ensō pressure curve**
```
pressure 1.0 ┤▁▆███▇▇▆▆▇▆▅ │ ▅▄▃▃▂▂▁ ← lifting, drying 0.3 ┤ └──────────────────────► path (≈330°, gap left open) press in steady lift
```

**Composite**
```
rice paper (texture) × ink layer (multiply) = final ink layer: every bristle dot at 10–44% darkness + faint bleed halos
```

**Critical thinking:**
sumi-e values a single unrepeatable stroke; digital tools value undo. Does removing undo make better art, or does undo let people explore more? What would a "no undo" mode do to your design process?

**Lateral thinking:**
the ensō is a whole philosophy in one circle, and your bot is basically an ensō with eyes. Is there a deeper brand idea in that: incomplete, human, calm?

**First principles:**
why does a brush that runs dry make a more expressive mark than one with endless ink? What does the texture of depletion tell the viewer about time and motion?

- How did 1960s studios animate ink-wash films?