The strip under the menu, writ large and yours to steer. Every point of the plane is a Julia set: pick a number c, and the set is every z that never escapes under z → z² + c. Drag the picture and c moves with you, by less the deeper you zoom, and stays where you let go. Leave it, and it wanders off along the walk that Julia charted for the strip.
The small map is the Mandelbrot set, the catalogue of every c: inside it the Julia set is one piece, outside it a cloud of dust, and the edge is where the pictures are. The wander keeps just outside that edge, on an equipotential of the set, which is what the Julia script works out. The drawing is the graphics card's: every pixel runs its own orbit, three hundred steps at most, sixty times a second. Letting go of a view you like puts c and the zoom in the address, so the link brings it back; pinning it keeps it from wandering off while you look.