Exercise: Dragging a Julia seed
When you view a Julia version of a fractal, you can manually change the Julia seed in the Set Julia Seed window. To get an animated view of a Julia whose seed changes over time, drag in a non-Julia window to adjust the Julia seed value, as follows:
1) Create a fractal or open an existing fractal, preferably of the Mandelbrot type.
2) Press CTRL+SHIFT+D to open a Julia window of the same type of fractal, and make it so that the two windows don't overlap.
Initially, the Julia window uses the center of the Mandelbrot window as its seed location.
3) alt-click in the Mandelbrot fractal window to adjust the Julia seed, thereby causing dramatic changes in the shape and look of the Julia set.
4) alt-click and drag around in the Mandelbrot window to continually update the Julia window using the changing seed value.
Notice the fundamentally different types of Julia sets that you get when you move the seed onto the black area of the Mandelbrot set as opposed to the coloured areas.
Also notice that the type of Julia set you get is thematically similar to the type of Mandelbrot set you would get if you zoomed in on the area of the Mandelbrot set where the seed is.
For best results, keep the Julia window relatively small so that it can be updated more easily.
Or, adjust the Julia Seed Dragging settings in the Miscellaneous page of the Preferences window.
Or, read up on Julia sets.