... by: Pieter, Newtown, AustraliaHi Andrew
Beside Example 1 you say "the candidate number is 1 and F9 is the Hinge. It can see a 1/2 in D9 and a 1/4 in F1. We can reason this way: ... "
I find it interesting your reasoning or explanation here starts from the wings and then uses Naked Pairs, and doesn't work outwards from the Hinge (as you do in Y-Wings). I always seem to reason from the Hinge outwards. If F9 is a 2 then D9 is a 1, or if F9 is a 4 then F1 is a 1, or F9 could be a 1, therefore any 1 visible to all three cells must be removed, in this case in F7.
In WXYZ-Wing you explain it quite succinctly by saying "The easy principle is that each possible value of the hinge cell results in a Z value in one of the cells in the [WXYZ]-Wing pattern, thus leaving no room for a Z on any cell all [four] can 'see'."
I like the idea of "Bent Quads" for WXYZ-Wing, so I suppose XYZ-Wing could be considered a "Bent Triple"?!