rebol [
    title: "doodlepad"
    author: 'vpavlu
    date: 23-jan-2003/16:04
    home: http://plain.at/vpavlu
]

prev-pos: none

lay: layout [
  box 200x200
  effect [
    draw [
      pen 0.0.0
    ]
  ]
  feel [
    engage: func [ face action event ][
      if action = 'down [
        prev-pos: event/offset
        append face/effect/draw reduce ['line prev-pos prev-pos]
        show face
      ]
      if find [over away up] action [
        ;remove back tail b/effect/draw
        append face/effect/draw event/offset
        show face
      ]
    ]
  ]
]

view lay