In a comment on a Man at Arms: Reforged video I’ve learned that
[Roger Zelazny] did draw [Corwin’s sword Grayswandir] for a fan that lives here in Maryland. He drew it as a saber with a ships sail guard with the pattern overlayed on it. not highly detailed but I was shown the drawing and letter in the mid 1990's. I wish I had a copy of it!
Are there any such pictures online of what Zelazny intended the Pattern to look like? Either a drawing by Zelazny himself (as in the letter described above) or fan-art plausibly claiming to follow such a drawing by the series’s author.