# Perturbation

Perturbation is a simple trick which changes the point at which orbits start. Traditionally zero is used, but other values can generate interesting results too.

On enabling this function from the menu, you will be asked for a complex number specifying the perturbation. It is a toggle; selecting it again resets the perturbation to zero without prompting.

It can be used to specify a complex number representing a point on the screen. If you hit the `B`

key instead of using the menu, the current mouse position is used. This too is a toggle, so `B`

again will disable perturbation by setting it to zero.

This function only has an effect for certain formulae (like the Mandelbrot set) and only then in Mandelbrot mode.

**Available as**: menu item

**Syntax**:(perturbation complex)

This is the scripting-language variation of the perturbation function. Instead of toggling, you always specify the perturbation to use. Use 0 0 to disable perturbation.

**Available as**: command line option, command