  We give a method to find quartic Heisenberg invariant equations for Kummer
varieties and we give some explicit examples. From these equations for
g-dimensional Kummer varieties one obtains equations for the moduli space of
g+1-dimensional Kummer varieties. These again define modular forms which vanish
on the period matrices of Riemann surfaces. The modular forms that we find for
g=5 appear to be new and of lower weight than known before.
