spiralh =: (,:@i. , ] + [: |:@|. spirals) ` ((1 0$0)"_) @. (<:&0) spirals =: ,:@i. , ] + [: |:@|. [: spiralh <: spiral =: ([: >: spirals)"0 2!:55[0[ 1!:2&2 spiral 5".>{: ARGV