. The speed button Start is then
disabled and the speedbutton Stop is enabled.
If at least one computer is selected for each fractal the calculation
can be started by selecting the Start command from the Calculation
menu or by clicking the speed button . The speed button Start is then
disabled and the speedbutton Stop is enabled.
When all the fractals are calculated and drawn the speed button Start will be enabled and the speedbutton Stop will be disabled and the calculation can be restarted.
You can stop the visualization by selecting the Stop command from the
Calculation menu or by clicking speed button 
. Notice that the
processes that are calculating won't be stopped and they spend
processor times until they are finished.