If you recorded where you left it, you may be able to retrieve it. Double-inspect every area. Keep trying to loosen them and take them with you. Experiment with Trinity . There is a lot to enjoy here which has nothing whatsoever to do with solving the puzzle.
Strange things happen.
And of course, experimentation may turn up facts which are important, as well. Ask questions of the people you meet. For instance, if you don't know what a gnomon is, ask the lady feeding the pigeons. Or if you don't know what a perambulator is, ask. Keep track of time by glancing often at your wristwatch.