The Mandelbrot Set
Square and add. Forever.
For each complex number c, iterate zₙ₊₁ = zₙ² + c starting from 0 and ask whether the sequence stays bounded. The black blob of points that do is the Mandelbrot set — one of the most intricate objects ever drawn. Zoom anywhere on its edge and the structure never simplifies.
z₀ = 0, zₙ₊₁ = zₙ² + c
