jigsaw puzzle solving
**Jigsaw Puzzle Solving** is a **self-supervised pretext task where the model is trained to predict the correct spatial arrangement of shuffled image patches** — requiring the network to learn spatial relationships, object structure, and visual semantics.
**How Does Jigsaw Puzzle Solving Work?**
- **Process**: Divide image into a 3×3 grid (9 patches). Shuffle them into one of N predefined permutations. The network predicts which permutation was used.
- **Permutations**: Typically 100-1000 selected permutations (out of 9! = 362,880 total).
- **Architecture**: Siamese-style — each patch encoded independently, then combined for classification.
- **Paper**: Noroozi & Favaro (2016).
**Why It Matters**
- **Spatial Reasoning**: Forces the model to understand spatial relationships between object parts.
- **Feature Quality**: Learned features transfer well to object detection and segmentation tasks.
- **Historical**: One of the pioneering pretext tasks that launched the self-supervised learning era.
**Jigsaw Puzzle Solving** is **teaching AI spatial common sense** — learning that the head goes above the body and the legs go below, all without human labels.