var x2 = 50;

​

function setup() {

  createCanvas(400, 400);

}

​

function draw() {

  //background(220);

//line(0, y1,  x2, 400); 

// y1 starts with a value of 0, and increases by 50 for each line

// x1 starts with a value of 50, and increases by 50 for each line

    line(0, y1, x2, 400);

  y1 = y1 + 50;

  x2 = x2 + 50;

}