oneshotlm
Compare all models on this prompt →

Double pendulum · claude-opus-4.8

Simulate a chaotic double pendulum on a canvas using the correct equations of motion, drawing the arms and a colorful fading trail of the tip.

⛨ sandboxed Open in new tab ↗
transcript · 4 messages
user

Simulate a chaotic double pendulum on a canvas using the correct equations of motion, drawing the arms and a colorful fading trail of the tip.

assistant
thinking
I'm creating a self-contained HTML file that simulates a double pendulum system.
write index.html (6997 bytes)
toolResult

Successfully wrote 6997 bytes to index.html

assistant

Created `index.html` — a self-contained chaotic double pendulum simulation. **Physics:** Uses the correct double-pendulum equations of motion (full nonlinear angular accelerations with coupled masses/lengths), integrated with **RK4** and 6 substeps per frame for numerical stability. **Visuals:** - Two rigid arms drawn from a fixed pivot, with bobs sized by their mass sliders. - A colorful **fading trail** of the tip that cycles hue over time and fades toward the tail via alpha, painted over a semi-transparent background wash for a motion-blur glow. **Controls:** live sliders for gravity, both masses, both lengths, damping, and trail length; a randomize/reset button; and click-to-reposition on the canvas. It's DPR-aware and resizes with the window.

TAKE IT TO CODE

A single self-contained HTML file — copy it and open in any browser, or reuse the prompt with your own pi-agent run.

RUN

modelclaude-opus-4.8
vendorAnthropic · Claude
harnesspi-agent
generated2026-07-08

EVALUATION

4/5 working

Double pendulum swings realistically with a colorful fading rainbow trail, controls visible but keyboard/click inputs seem to just reset via click canvas.

Vision grade · anthropic/claude-sonnet-5

MEASUREMENTS

Raw readings from the capture, not a verdict — the grade above is the only judgement. Percentages are how much of the screen changed; the measure under-reports sparse motion on a dark background.

idle motion0.6%
on click1.0%
on drag0.0%
on wheel1.0%
on enter + space1.1%
on arrow keys1.5%
on w/a/s/d1.4%
frame spread14.7 / 255
console errors0
js errors none

METRICS

runtime44.4s
tokens in3.8k
tokens out4.1k
cached4.5k
cost / run$0.1253