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Strange attractors: bounded, non-periodic, fractal invariant sets.
Lorenz (1963): First discovered strange attractor. σ=10, ρ=28, β=8/3 gives the iconic butterfly.
Lyapunov exponent λ₁ ≈ 0.906, dim ≈ 2.06.
Rössler: Simplest 3D continuous chaotic flow. Single funnel structure.
Thomas: Cyclic symmetry dx/dt = sin(y)−bx, fully symmetric under cyclic permutation of axes.