Structures of even smaller size are vortices in thin films and B loch lines in bulk ... perpendicular short N Ñeel wall segments ( the 'cross - ties ') periodically lining ...... 3 4%` ,. (2.16 ) provided that the solution to (2.5) ( 2.7 ) is su ffi ciently regular ; the ...... schemes which perform remarkably well in practice: in general, they do.