In "Word Ways Challenges" in the February 1979 issue, Philip Cohen and the editor asked "Can any form (diamond, pyramid) contain all 26 letters?" This well-nigh-impossible challenge has now fallen, with the double nine-diamond presented below.
"A Pangrammatic Diamond,"
Word Ways: Vol. 17
, Article 5.
Available at: https://digitalcommons.butler.edu/wordways/vol17/iss1/5