As you're only interested in showing one hemisphere at a time, wouldn't a simple three-face isometric display be sufficient? http://docs.bentley.com/en/MicroStat...s/standard.jpg shows a basic isometric projection of a cube and also offer the suggestion of using a "faded" and reversed backdrop for the backside of the cube. Then left and right directions would rotate the cube around the axis through the top and bottom faces, while up and down would make the top or bottom face visible. It would be, in effect, an "actual" 3D board while using only simple 2D graphics. If you'd like to have all faces visible at once, simply have two views.