Handwritten digits

load_digits() — 1,797 real handwritten digits, each an 8×8 grid of grey values. Shape (1797, 8, 8).

Ships inside scikit-learn. Flattened to (1797, 64) it becomes the workshop’s standing example of a data matrix: standardized in section 03, contracted into a similarity matrix in section 06, and factorized in section 09.