String Art

var dx1;
var dy1;
var dx2;
var dy2;

function setup() {
    createCanvas(400, 300);
    background(200);
}

function draw() {
    drawLines(0, 50, 400, 200, 150, 300, 100, 100, 50);
    drawLines(100, 0, 300, 300, 150, 200, 350, 100, 50);
    drawLines(0, 200, 300, 100, 300, 300, 400, 300, 50);
    drawLines(350, 100, 300, 200, 150, 300, 350, 100, 50);
    noLoop();
}

function drawLines(x1, y1, x2, y2, x3, y3, x4, y4, numLines) {
  dx1 = (x3-x1)/numLines;
  dy1 = (y3-y1)/numLines;
  dx2 = (x4-x2)/numLines;
  dy2 = (y4-y2)/numLines;
  line(x1, y1, x3, y3);
  line(x2, y2, x4, y4);
  for (var i = 0; i <= numLines; i += 1) {
      line(x1, y1, x2, y2);
      x1 += dx1;
      y1 += dy1;
      x2 += dx2;
      y2 += dy2;
  }
}