The sibling comment gives what is probably the correct answer (visitors), but in fact self-timers for cameras have been around for 100 years or so: https://www.

The sibling comment gives what is probably the correct answer (visitors), but in fact self-timers for cameras have been around for 100 years or so: https://www.photo.net/discuss/threads/dating-the-original-kodak-self-timer.375928/ https://www.photo.net/discuss/threads/dating-the-original-ko...