Once, while tripping, I was trapped for a short time in a thought trail about sound. I reasoned that every sound had a physical explanation. So that, for example, the sound heard when busting a wooden pencil apart resulted from the breaking of bonds/particles that made up the wood and lead. It was then that I happened across the concept of digital sound, and it was beginning to look as though I would get pulled into a mind loop for a long time, but luckily I was distracted by something.