This is the graph of the polynomial t_{50}(*z*)
of a sequence of cosine polynomials {t_{n}(*z*)}
which aproximates locally uniformly the Riemann x
function (in Titchmarsh's book on the Riemann z
function x is denoted by X).
As you may observe our "Christmas tree" logo is a part
of the above graph. Even more important observation is that ALL
the zeros of t_{50}(*z*)
are real. Is the same true for every natural *n*?!?