Jim and Patrick, thanks! Glad you like it. I gave it to my Dad last week and he enjoyed it, so success!

As far as your question, Patrick, I'm not sure I understand it. The joint is a pretty standard half blind dovetail, with the spacing set up to hide the grooves housing the blue mahoe top and bottom panels. The last tail at the top is really more or less a half-tail to the extent it has one angled side and one that is much closer to square - very slight angle. Maybe the straight on pic shows it better:



I'm not sure what look like it is curving to you, but if you mean the long sides coming over the short sides, the long sides are untouched natural edges from the tree - ie, this was the surface right under the bark -- nature shaped it!