In the August 1971 Word Ways, Darryl Francis challenged the reader to produce a hyperhypercube (a word cube in five dimensions) out of 80 suitably-chosen two-letter words. This array on the right represents the best solution I have been able to obtain. 73 of the words are found in Webster's Second or Third Editions (one, OP, is found in the Addenda to the Third); 5 words from Webster's First Edition; 2 (UA, UK) are found in the Times Index-Gazetteer.
"A Hyperhypercube of Side Two,"
Word Ways: Vol. 4
, Article 3.
Available at: http://digitalcommons.butler.edu/wordways/vol4/iss4/3