> > ...by the way can you construct a situation requiring > > three passes?? > > I suppose this is a three pass position. > > > 6 . . . . . . . . . > 5 * * * * * * * * * > 4 o o o o o o o o o > 3 * * . o . * * * o > 2 . o * o * o . * o > 1 * * * o * * * * o > A B C D E F G H I > I agree, well found. Thank you. ...now how about 4 ;-) ! Mick.