This eight-sided die has only four outward facing faces.
If it lands with a hole up, you can look throuh the hole to read the number off the backside of a face.
Alternatively, you can subtract the outside number of the bottom face from 9, as for resons of balancing, the pips on each face add up to nine.
In this version, the Borromean rings
that make up the boundary have been thickened so that the pips do not impede the rolling.
The die is fairly balanced because its convex hull has sufficient symmetry and I have calculated the center of mass to be less than 3 micrometers away from the geometric center.
Available in four sizes.