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