I saw your exploit! I had intended to disallow repeated words anywhere in the game, but didn't have time to implement it.
Yes, you're also right about parallel words in regular Scrabble, but this isn't regular Scrabble. Words of length 2 are ignored anyway.
Thanks for playing for so long by the way. You discovered a bug I wasn't aware of where if you scroll far enough, the background tiling stops repeating!
I just wish I had enough time to polish this properly and get it finished. Ah well, too big and too complex for one person to build in a few days.