alt Hacker News> We verified this by taking a recently-calibrated reference dog, Scribble, depicted in Figure 6, and having him bark three times, thus simultaneously factorising both 15 and 21. This process wasn’t as simple as it first appeared because Scribble is very well behaved and almost never barks.
one can always press the door bell button - works like a charm with my Chihuahua. Though he prefers to factorize numbers more like 529 than 21.