Points in the keep set kc are black everything else (ie white and shades of grey) is in the escape set Ec.

The red circle is the point c. Click on it and drag it to see the associated filled in Julia Set.
Shift-click will restrict movement of the point to the circumfrence of the circle with radius |c|.
Ctrl-click (Alt-click on Mac) will restrict movement of the point to the radial line connecting c.

Clicking anywhere apart from the red circle will draw the iteration sequence { z0 } for the point clicked.
Click and drag to move the start point of the iteration sequence.

Keys 1 to 9 set the view scale with 1 being the default scale.
Key S hides/shows the current iteration sequence.

Source code: julia_set_2

Built with Processing