val wid = 800

size(wid, wid)
frameRate(3)
colorMode(HSB)
background(250,255,0)

val backColor = color(30, 255, 255)
var siz = 1
def upperLeft = (wid -siz *2) / 2
def lowerRight = wid/2 +siz

def draw() {
  noStroke()
  fill(backColor)
  rect(upperLeft, upperLeft, siz*2, siz*2)
  stroke(0)
    
  //val mirrorPivot = new Pt(lowerRight, upperLeft)
  //var p1 = new Pt(upperLeft, upperLeft)
  
  for (movingDiagonal <- upperLeft to lowerRight) {
    line(upperLeft, lowerRight, movingDiagonal, movingDiagonal)
    line(lowerRight, upperLeft, movingDiagonal, movingDiagonal)
  }
  siz += 1
  
  if(siz >= wid/2) noLoop()
}//*/