Several are really common, others I've seen a few examples of. There's some that seem to be balanced around a central point in a chart-like way,
and others that kind of peak at a central point as if someone shook a rope on either side and the rope dissolved into sand -- definitely not chart-like.
There are a few I'd like to see on a chart, as they too look projection-worthy.
Reminds me a little of John Ehler's more colorful stuff, which is on the indicator side of things.
