d4 Bicone

A unique d4: two cones, joined at the base. The resulting figure is then slightly squashed such that there are four landing positions each with equal probability. When tossed or rolled, it will wobble until a result (1 through 4) is shown facing upward. To my knowledge, this is the first bi-polar shaped d4, which the possible exception of a sphericon dual. It has been previously stated that the smallest possible dipyramidal die is a d6. However, I feel this to be a four sided figure that is closer to the class of dipyramids than it is to any trapezohedron, so I suggest that this is the shape 2 faces below the trigonal dipyramid.