OfTheShapeOf​(AngouriMath.​Entity.​Matrix,​AngouriMath.​Entity)

simplified, a simplification of a matrix of source's shape, as a matrix. A
1x1 matrix simplifies to its entry, and a cast threw InvalidCastException for the row echelon forms, and so for
the rank, of every 1x1 matrix. A larger one simplifies to something that is not a matrix only where an entry has
no value, which is a fault and still raises: wrapping it as a 1x1 matrix would give it a rank of 1.
https://github.com/asc-community/AngouriMath/issues/2269,
https://github.com/asc-community/AngouriMath/issues/2270