CISRA Puzzle Competition 2011  Hints
5A. Latin Pipes II
 Yes, fitting the pipe pieces is quite hard. Ignore the black
intersection dots for the moment; they're useful only when you've
solved all the pipe pieces.
 Try annotating each boundary with a "x" (a pipe doesn't go through
this boundary) or "" (a pipe goes through this boundary) when you know
what it must be. When traversing any given row, there will be exactly
five "x"s encountered: two will surround a straightline pipe, and
two will surround the "." nonpipe. The same is true for each column.
 The edges wrap (i.e. the top and bottom pieces of the same column
must match, and the leftmost and rightmost pieces of the same row must
match.) If you get stuck, you might be able to make some progress by
trying to deduce the possible positions of the "." pieces. When you've
finished, try colouring in. What does the picture look like?
