This is cool! It might sound silly, but figuring out `None` and `...` indexing in numpy was one of the more delightful moments of learning as a programmer for me.

Tangent: I wish we had not settled on the word "tensor" for multidimensional arrays. Yes there is some isomorphism with the multilinear map definition, but the huge majority of code using >2D arrays has nothing to do with multilinear maps.