Recently, I used a computer to look for 5x5x5 word cubes: symmetric patterns that spell five-letter words in rows, columns, and whatchamacallits (is there a name for vertical 1x1x5s?). As far as I know, the only previous example was constructed by Peter Graham and published in Omni in July 1987. But his solution uses REDAN and SARUM.
Knuth, Donald E.
"5X5X5 Word Cubes By Computer,"
Word Ways: Vol. 26
, Article 12.
Available at: https://digitalcommons.butler.edu/wordways/vol26/iss2/12