Because the bugs leave behind poison trails, no path can cross another, and no path can cross itself. When you are finished, every square must have been traversed once and only once.
_ _ _ _ _ _ _ |A|_|B|_|_|_|C| |_|_|_|_|d|_|_| |_|_|D|_|_|_|_| |_|_|_|E|_|_|e| |_|_|_|F|_|_|_| |_|_|_|_|_|_|_| |a|_|_|_|b|c|_| |f|_|_|_|_|_|_|
Prove whether or not there is a solution.
If you think there is a bug in the problem, can you move EXACTLY one bug EXACTLY one square from its original position (not diagonally) and find a solution? Would it be unique?
The bulk of this problem was created by Clifford Pickover