User blog comment:Googleaarex/Make an extension of the notation/@comment-5029411-20140926211035/@comment-190.13.28.186-20140929220010

a(-&&-)-b = a(-&(-&(-&(-&...)-)-)-)-a with b levels.

a(-&&&-)-b = a(-&&(-&&(-&&(-&&...)-)-)-)-a with b levels.

Limit is a(-&&&...&&&-)-b