[vikingerik]

The dice on that page are in fact the same on all sides. For each of those dice, every face on it is the same as every other face, the same shape and attached to the same adjoining faces at the same angles.

They're not regular - the faces are not regular polygons - but that's not a requirement to have an equal chance of landing on each side. The standard d10 is an example of this in itself.

[unholiness]

I think he means the same distance between opposite faces, the quantity that was discussed in the article.

The skew dice faces are all identical but none are even parallel.

[vikingerik]

Parallel opposite faces isn't a requirement for fairness either. A standard d4 doesn't have that.