Single Comment

Regarding the name "Unicorn", I originally preferred to use it in my 4D variant (rather than "Nun", or any other name), until I saw the wiki link on fairy chess pieces, which didn't appear to me to include the way I was using "Unicorn". Apparently I looked in haste, because it now appears to me that it does. I'll go back and edit my submission to change the name "Nun" to "Unicorn".

Back in the 1980s when I came up with the idea of a 4x4x4x4 4D chess variant, in a different city than I am now, I had borrowed a library book on fairy chess which I recall only a very small number of things about (not including the title or the author's name). One thing the book showed was a diagram for a 5x5x5x5 4D chess variant, with the 4D fairy piece type Balloon included. As an aside, I at once preferred a 4x4x4x4 board concept, to have an equal number of light and dark squares, but later I saw that 5x5x5x5 at least often allows a knight more legal moves depending on location.

The book also mentioned the "Unicorn" as a 3D piece. It likely matched wikipedia's description of its movements. If so, I'd note that nowadays this use of "Unicorn" doesn't quite make so much sense to me, however, since the mythical beast is virtually a horse, and it thus seems desirable to me that any such named piece would have some knight-like property to it (regardless, in the 1980s, not thinking of this, I wanted to use the name "Unicorn" for a piece, since it's charming for a name). In spite of this, I'll drop the use of "Nun", as mentioned.