Shell Game World Model Demo (~18M)
A small shell-game world model that predicts which cup holds a hidden ball from a single contact-sheet image.
Links
- GitHub repo: https://github.com/illegalcall/jepa-track-hidden-ball
- Upstream base repo: https://github.com/lucas-maes/le-wm
- License: MIT
- Local demo server:
serve_demo_ui.py - Single-sheet inference script:
demo_jepawm_predict.py
What This Model Does
The bundled checkpoint is designed for a shell-game benchmark:
- three cups
- one hidden ball
- smooth cup swaps
- predict the final cup from the observed sequence
The repo slices a contact sheet into ordered frames, runs the checkpoint locally, and returns the final cup prediction.
Main Result
Hidden-ball balanced accuracy:
| Setting | Result |
|---|---|
1 swap |
100.0% ± 0.0% |
3 swaps |
74.3% ± 2.9% |
1-2-3-4 swaps |
75.8% ± 2.7% |
1-2-3-4-5 swaps |
74.5% ± 1.2% |
1-2-3-4-5-6 swaps |
73.7% ± 1.1% |
Random chance is 33.3%.
Important Caveat
This is not a plain next-step JEPA checkpoint.
The working shell-game variant uses explicit hidden-state supervision during training. Pure next-step JEPA-style prediction did not solve this benchmark.
Quick Start
git clone https://github.com/illegalcall/jepa-track-hidden-ball.git
cd jepa-track-hidden-ball
python3 -m venv .venv
source .venv/bin/activate
pip install -r requirements.txt
PYTHONPATH=local_inference_assets python3 demo_jepawm_predict.py \
--checkpoint /path/to/lewm_auxonly_123456_h12_epoch_12_object.ckpt \
--sheet demo_cases/case_1/sheet.png \
--history-size 12 \
--device cpu \
--output result.json
Local Demo UI
python3 serve_demo_ui.py --host 127.0.0.1 --port 8123
Then open:
http://127.0.0.1:8123/demo_ui/
Model Size
This checkpoint has 18,048,683 trainable parameters.
Files In This Release
lewm_auxonly_123456_h12_epoch_12_object.ckptlocal-ui-overview.pnglocal-ui-output-card.png
Limitations
- this checkpoint is specialized to the shell-game benchmark in the repo
- it is not a general-purpose vision model
- retraining from scratch still depends on upstream LeWM / stable-worldmodel code
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