  This is a personal tribute to Lance Littlejohn on the occasion of his 70th
birthday. It is meant as a present to him for many years of friendship. It is
not written in the "Satz-Beweis" style of Edmund Landau or even in the format
of a standard mathematics paper. It is rather an invitation to a fairly new,
largely unexplored, topic in the hope that Lance will read it some afternoon
and enjoy it. If he cares about complete proofs he will have to wait a bit
longer; we almost have them but not in time for this volume. We hope that the
figures will convince him and other readers that the phenomena displayed here
are interesting enough.
