Ah, thanks, looks much better! Yeah, I just took the original and quick'n'dirty-added the second condition, all the while thinking "hmm..." - and quickly losing

Ah, thanks, looks much better! Yeah, I just took the original and quick'n'dirty-added the second condition, all the while thinking "hmm..." - and quickly losing interest again. :) Regarding tree mutation - I have to admit, it gives me some petty satisfaction looking at the errors thinking "Where is your sticky NOW!"