/**
 * Loop to grid.
 *
 * <p>Elie Zananiri<br>
 * CART 253, Winter 2008</p>
 */
 
size(300, 300); 
background(255); 
stroke(0);

// remember that width == height
for (int i=0; i < width; i = i+20) { 
  // draw a vertical line
  line(i, 0, i, height); 
  // draw a horizontal line
  line(0, i, width, i); 
}