I made several of these, but sorry -- no real pattern. What I used was an idea on the back of the Marilyn Doheny 9 degree circle wedge ruler. To make the hole for the tree, just don't put the circle in the center -- and the points are one option for the finished top. I did a couple as QAYG and made them completely reversible. I also bought the extension for the 9 degree ruler since DD wanted one that was much bigger than the 50" diameter that you get with just the regular ruler.