The d4 of the "Open" series. Labeling the faces of a d4 doesn''t make as much sense, so the tilted faces now reside under the vertices.
(Compare this with the "Tetrasphere" by friz at http://www.shapeways.com/model/152256/tetrasphere.html which is similar)
2.336 w x
2.336 d x
0.92 w x
0.92 d x