As discussed in previous posts, a weighted die is no barrier to a secure bitcoin seed provided sufficient throws are made.
To demonstrate how difficult it is to spot a very weighted die I made an 18mm die which has a center of mass 1.7mm lower than the center of volume.
After a small number of throws it appears that the method of throwing has a big impact on how the result. Time dependent I will try and do some longer tests and perform an analysis on the result.
Shallow throw across a table:
Roll in hand and drop onto table:
The files are online so you can print your own.
V1 is a sharp edged die (casino style)
V3 is chamfered
Future iterations could use captured nuts / coins to further skew the center of mass away from the center of volume.