A couple weeks ago I was clowning around with the girls while they were in the tubby, singing single notes and having the girls sing the same notes to match. I was actually VERY impressed with their accuracy, especially because, gentle reader, while my daughters are always ENTHUSIASTIC singers, they are not always ACCURATE singers.
Unlike their mother of course. Ahem.
Anyway, I wanted to then replicate the trick on video, but, um, yeah, well.