No, not some colorful creature intended to help wash out reality, instead a way of joining two pieces of wood.
Yesterday, I worked on moving some dirt around in the neighborhood park to build a small jump line and then moved a few logs around, which is the part I get really excited about. I haven't gotten to do wood work in a bit. Pictures will follow in the next few days of the beginning of the project. ANYWAY, the whole butterfly joint thing and the above photo is relevant I promise.
To link logs together there are a number of techniques, I have used dovetail joints before and will probably use them again, but I have never had the opportunity to use a butterfly, which I really like the idea of. There are a number of factors that have me headed in the direction of using no metal fasteners for wooden structures. However, I need to experiment a bit more to get the craftsmanship and detail I would like to have for something like that. The photo at the top is of a table made by George Nakashima, a Japanese woodworker who creates amazing furniture and is know for his use of butterfly joints to fit wood together. Look him up, you just might learn something and get to see pretty pictures along the way.