size (600,400);

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
int endlegs = 150;

stroke(0);
while (x <= endlegs) {
      rect(x,y,x,y+len);  ///draw each leg
      x = x + spacing;  ////Add spacing to X
}