User blog comment:KthulhuHimself/Terminal array notation./@comment-25601061-20151028175208/@comment-25601061-20151028191206

Hmph.... let me try again. (again, described in similar way as KthuluHimself does):

So, let's redefine PP<#>. First, we replace PP<#> with P<(P<#>)>. Then, in a similar way, we could have  P<(P<(P<#>)>)>, and even  P<(P<(P<... P<(P<(P<#>)>)> ...>)>)>! But what's  P<(P<(P<... P<(P<(P<#>)>)> ...>)>)>? It PP<#>!

(should i add more stages to this?)