Can you try this in your draw()?
background(128);
line(width/2,height/2, location_x, location_y);

This draws a line from the center of the screen to your specified location location_x, location_y. Each time you run draw(), update this location.

Sorry if i didn't express my question very well, an example of what i was looking for was something along the lines of the following (probably not the most efficient way of doing it):

   stroke(255);
   strokeWeight(6);
   line(400, 300, i, 700-i);
   if ( i < 600 )
   {
      i = i + 3;
     
      if(i >= 600)
      {
        noLoop();
      }      
   }