sudoku ? (need some help/advice how to close a surface)

 From:  Frenchy Pilou (PILOU) 14 May 2008  (3 of 28) 
1608.3 In reply to 1608.1 
A simple sweep?
Curiously the inverse gives not a such sweet result :) (Start / End as rail1 & 2)


EDITED: 14 May 2008 by PILOU