These 6 diagrams represent a single starting setting to which small changes have been made by relocating a single White piece. The result is 6 different, not very difficult, ideas. White can play and win 5 of the 6, but cannot play and win the other.
Question for Solvers: "Which one cannot be won?" THAT IS ALL. Alex M. and John Webster, working together at the 2012 Virginia Tourney, solved the puzzle from the diagrams in about 10 minutes.
Question for Composers: "Which is the best problem idea?" THAT IS JUST THE BEGINNING. The best problem ideas become the starting points of setbacks to camouflage those ideas and make them more difficult.
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I will post the solutions next week, together with references to the known, more difficult, published setbacks.
I would be interested in whether problem composing is a topic of interest to anyone on this Forum.