Click on the image for a video.
See also Josefine Lyche's "Grids, you say?"
I prefer Lyche's versions of the diagonal
3×3 grid. Her versions have no lettering.
(This post was suggested by a photo of magical sigils
that Lyche posted a few hours ago at Facebook.
The above seems to be another such sigil that may
or may not be intended to function like those posted
today by Lyche.)