Something old something new

Bought a new sketchbook, Daler Rowney 150gsm acid free cartridge paper, it's got a good surface, and takes pencil well... anyway, I was scribbling on it over lunch, and ended up drawing a stumpy crocodile.

I was sure I'd drawn something like it years ago, so had a quick rifle through some old boxes in the basement and found a page with a couple of crocs... I've no idea what it was for, but from the squiggles it looks like it was part of a huge series of books I did in the 90's for Harper Collins Educational.  What's weird is that I probably work with people who learnt to read using these things...