Could see right away that the roof was impossible, so to paraphrase Mr. Spock, "Whatever remains, must be the solution."
The solution was evident fairly immediately and so it was simple gameplay. But I would like to take the opportunity to clarify what @Don G Rowe quoted. There was an episode of Star Trek in which Spock said s, “An ancestor of mine maintained that if you eliminate the impossible, whatever remains, however improbable, must be the solution.”. That was one of the 12 times that Star Trek reference or crossed with Sherlock Holmes. The original quote came from their Sherlock Holmes novel "The Sign Of The Fout", published in 1890, and was "How often have I said to you that when you have eliminated the impossible, whatever remains, however improbable, must be the truth?”. I know some other totally useless information as well if you ever have need of some!
