“When you have exhausted all possibilities, remember this: you haven’t.” Pastor Robert Schuller (1926 – 2015). Also sometimes improbably attributed to Thomas Edison (1847 – 1931).

And then there is this: Once you have exhausted all possibilities, there will be one solution, simple, obvious, and highly visible to everyone else. Adapted, Murphy’s Law and Other Reasons Why Things Go Wrong, Arthur Bloch.