Adding if and else function

If the mouse is within a certain range then the colour of the stroke
will change from purple to white. Just a progress shot
More weekly exercises
If colour change

The image inverses when the mouse passes the halfway point of the
window. An if function has been added so that the image is purple when
the mouse is positioned before the halfway point and it changes to
white after the halfway point.
Origin change and random change

Changed the point of origin so that the image moves freely around the
window in relation to the mouse position rather than being stuck in the
centre. Also randomised the angle from PI to 100 to create an explosive
output.