Proposed by Michel Hénon in 1976 as a simplified model of the Poincaré section of the Lorenz system, the Hénon map iterates a simple quadratic rule in two dimensions. At the classic parameters a = 1.4, b = 0.3, the attractor is a fractal with Hausdorff dimension ≈ 1.26. Zoom in anywhere and find the same banana-shaped folds repeated forever.