User blog comment:Wythagoras/Buchholz hydra/@comment-5029411-20130829204654

Array Hydra 2:

Array 2 Rule 1: (@\w[%]) = (0,0...0,0,@) (% 0's)

Array 2 Rule 2: (@\w[0]) = (@)

Limit: (1\w[ 1\w[...]] ) or psi_{chi(M^M)}(0)