Two letter words are pretty important to learn for playing scrabble. Once you've learned the list: Zo, Qi, Jo and the fact that X can go with any of the vowels (Ax, Ex, Xi, Ox and Xu) then you have an easy way to get down any of the difficult and high scoring letters.
When I was making a crossword recently I got thinking about the possibility of 3D crosswords. So you would have the across, the down and the out directions. Having so much connection makes it difficult to fit words together, but it became an interesting thing to think about. Taken in its simplest form I wondered if you could fit words into a 2x2x2 cube such that all 12 lines were valid words.
This was answered straight away by the word Aa (a type of lava flow found in volcanoes in Hawaii) by simply filling in all 8 boxes with the letter a. With less obscure words you can use the words No and On to fill in a cube with alternating Os and Ns.
But what about one without repeats? All 12 words must be unique.
After playing around with it for a bit, I've created this:
Words used (all scrabble legal):
Te- A musical note
To- As far as
Ab- Abdominal muscle
Er- Expression of hesitation
Ob- An objection
Or- An alternative
De- proposition meaning of or from in names
Re- A musical note
Be- To exist
Having worked at it a bit, the answer is none unique. but there are definitely not many distinct solutions. If you want to come up with your own then this list of 2 letter words will help. I think I might try to make a cryptic in a 3x3x3 cube with black square at the centre of each face and at the very centre.