To be continued…

import scala.util.continuations._

size(500, 200)
frameRate(15)

var cur: Unit => Unit = { (u: Unit) =>
  reset {
    var x = 0
    while(true) {
      x = (x + 1) % width
      background(255)
      color(0)
      line(width - x, 0, x, height)
      shift { k: (Unit => Unit) =>
        cur = k
      }
    }
  }
}

def draw() {
  cur()
}

… at Delimited Libations, Stimulated Saturdays, and Scala Days.