Rhythmic Motion

This morning, I awoke to a strange squeak in the ceiling. The house was resonating to some unknown rhythmic motion somewhere. The washer or dryer could do that, but they were silent, so the motion had to coming from somewhere else.

It must be an earthquake. I wondered if it was a Bay Area quake, or a Napa quake, or a Lake Tahoe quake. Perhaps the strange squeak in the ceiling could yield a hint. Since the quake seemed to be quite extended, I decided it had to be a large Bay Area quake rather than an abrupt Lake Tahoe quake.

Listening a bit more, I finally realized the rhythmic motion was Sparky in the other room scratching himself....