Variables are used for storing values. In this example, changing the values of variables 'a' and 'b' significantly change the composition.
Original Processing.org Example: Variables
// All Examples Written by Casey Reas and Ben Fry // unless otherwise stated. size(200, 200); background(0); stroke(153); int a = 20; int b = 50; int c = a*8; int d = a*9; int e = b-a; int f = b*2; int g = f+e; line(a, f, b, g); line(b, e, b, g); line(b, e, d, c); line(a, e, d-e, c);