// Learning Processing
  // Daniel Shiffman
  // http://www.learningprocessing.com
  
  // Example 6-3: While loop
  
  size(200,200);
  background(255);
  
  int y = 80;       // Vertical location of each line
  int x = 50;       // Initial horizontal location for first line
  int spacing = 10; // How far apart is each line
  int len = 20;     // Length of each line
  
  // A variable to mark where the legs end.
  int endLegs = 150; 
  stroke(0);
  
  // Draw each leg inside a while loop.
  while (x <= endLegs) { 
    line (x,y,x,y + len);
    x = x + spacing;
  }