Iteration: 400
Init rule:
z = vec2(x, y);
Update rule (Shift+Enter):
// you can use v1 and v2 z = vec2(z.x * z.x - z.y * z.y + x, 2. * z.x * z.y + y);

Q - A: Zoom
W - S: v1: 1
E - D: v2: 0