...since you have been interested in the matrix form of sqrt(-1), I thought you might also be interested in the book I recently came across as well, "The Naked Spinor: A Rewrite of Clifford Algebra".
...I can't recommend it, since I haven't read it yet. But from the introduction it sounds pretty interesting:
"Some ten years ago, your author stubled upon a change in the notation we use to write complex numbers. Instead of writing a complex number as a+ib, your author began to write a complex number as a 2x2 matrix. From nothing more than this change of notation, your author discovered the higher dimensional complex numbers. The higher dimensional complex numbers include the whole of Cliffor algebra and, with that, the whole of spinor theory. The change of notation simplifies and generalizes Clifford algebra and spinor theory."
Sorry for derailing your GitHub thread with an off-topic comment.
https://www.amazon.com/Naked-Spinor-Rewrite-Clifford-Algebra...
...I can't recommend it, since I haven't read it yet. But from the introduction it sounds pretty interesting:
"Some ten years ago, your author stubled upon a change in the notation we use to write complex numbers. Instead of writing a complex number as a+ib, your author began to write a complex number as a 2x2 matrix. From nothing more than this change of notation, your author discovered the higher dimensional complex numbers. The higher dimensional complex numbers include the whole of Cliffor algebra and, with that, the whole of spinor theory. The change of notation simplifies and generalizes Clifford algebra and spinor theory."
Sorry for derailing your GitHub thread with an off-topic comment.