Hello Oliver,
yes it really is interesting stuff the guy who invented it got an MBE i believe or something to that extent.
another reason strangely enough, was when my children were younger, they used to like watching Mr tumble (Justin Fletcher) to which i also believe uses it as well.
There was also this funny story that intrigued me, and that was, good old Justin was teaching the kids swear words in sign language, he got into a bit of trouble for that but i find it hilarious just thinking about it.