Langstrom's Pony

Here's another tune I was asked to post. Posting ponies; is that like Pony Express are are they just post ponies? Anyway, I'm never too sure of the first part but that wasn't the focus of the query to which I'm trying to respond here. I hope I haven't forgotten about any parts either. It's a good job that the latter bits (another equine apparatus related term) hadn't too many low notes as on finishing the tune I noticed that my foot joint (hoof?) had fallen off. I hope that the tune is OK, though, and promise that no animals were hurt in the recording of it.