Liner

Another Processing sketch

use the mouse (left and middle mouse[increase speed when pressed] and scroll[number of rectangles between), and the 1, 2,3,4 keys are  (decrease increase size of rectangles towards point a , and decrease increase size of rectangles towards point b) and the ‘r’ (randomize)  ‘m’ (toggle both lines moving)   ‘d’ (toggle distance between lines)  ‘b’ (background)

 

Click here to try it out