On Wed, May 03, 2006 at 08:14:54AM -0700, Eric Wald wrote: >I agree. The only thing I would do to improve it is to use slashes >instead of commas, to make the stacks explicit. > Initial Tree: ^1/2/3 > A Nest: ^3/2/1 Whereas I'd lose the punctuation completely: Initial House: <3 ^1 >2 Initial Tree: ^123 A Nest: ^321 All you then have to remember is "direction indicator first, and that's the top of the stack". R