A chaotic 3D attractor with four-fold symmetry
dx/dt = ax + yz dy/dt = bx + cy − xz dz/dt = −z − xy
The four-wing attractor (Liu 2009) exhibits chaos with four-fold wing symmetry in 3D phase space. Lyapunov exponent λ₁ > 0 confirms sensitive dependence on initial conditions — nearby trajectories diverge exponentially.