Ah, I love (at least the idea) of the APL languages. My go-to programming syntax mindbender is this video of programming Conway's Game of Life in APL:

http://www.youtube.com/watch?v=a9xAKttWgP4

J is like that but without the special keyboard. I haven't played around with J much, but I know that whenever I've finished a Project Euler problem and checked the forum afterwards for other solutions, the J folks have reduced my 100 line solution to one or two lines...