Lines

void setup() {

  size(400,400);

  background(0);

}

​

void draw(){

  frameRate(7);

  stroke (255,0,0); 

  line (0, random(200), random(200), random(200)); //top left

  line (random(200), random(200), 200, random(200));

  stroke (0,255,0); 

  line(200, random(200), 400, random(200)); //top right

  stroke (0,0,255);

  line (random(200), 200, random(200), 400); //bottom left

  stroke(random(255)); //bottom right 

  line(300,300,random(188,500),random(188,500));

}