[Retros] Bishop round trip

[Pascal Wassong]

Hello,

most of you know about the following problem by Michel Caillaud :

+---+---+---+---+---+---+---+---+

|*R | . |   | . |   | . |   | . |

+---+---+---+---+---+---+---+---+

|*P |   |*P |*P |*N |*P |*P |*P |

+---+---+---+---+---+---+---+---+

|*B | . |*P | . |   | . |   | . |

+---+---+---+---+---+---+---+---+

| . |   | . |   | . |   |*K |   |

+---+---+---+---+---+---+---+---+

|   | . |   |*N |   | . |   | . |

+---+---+---+---+---+---+---+---+

| . |   | . | P |*R | P |*B |   |

+---+---+---+---+---+---+---+---+

| P | P | P | B | Q | P | P | P |

+---+---+---+---+---+---+---+---+

| . |   | K | R | . |   | N | R |

+---+---+---+---+---+---+---+---+
r7/p1ppnppp/b1p5/6k1/3n4/3PrPb1/PPPBQPPP/2KR2NR
15.5 moves	(14 + 14)

1.Nc3 Nc6 2.Nd5 Nd4 3.Nxe7 Kxe7 4.Nh3 Kf6 5.Nf4 Kg5 6.Nd5 Qf6 7.Nc3
Qf3 8.exf3 Bd6 9.Bb5 Bg3 10.Bc6 bxc6 11.Ne2 Ba6 12.Ng1 Re8+ 13.Qe2 Re3
14.d3 Ne7 15.Bd2 Ra8 16.OOO


The white Knight g1 makes a round trip so that White has moves to
play.  (Unto Heinonen has published a longer are and more complicated
problem with the same idea).


Has anybody composed a SPG on the same idea with a Bishop ?


The reason for the round trip must be the lack of other moves to play,
no the need to loose (or gain) a tempo.

Best,
Pascal