(although they expressed some doubt about they being universal against changes of the interaction model, what, in view of the independence of the primary mass, should not be doubtful).\
The electron angular distribution does, of course, determine their lateral spread. It was shown (Giller et al. 2005a) that the lateral distribution of all electrons depended on the shower age only. Further studies for fixed electron energies showed their universal character and a dependence on age only (Giller et al. 2007, Lafebre et al. 2009, Giller et al. 2015). Unlike the electron angle dependent on its actual energy the lateral distance does depend on the earlier electron history - even a small angle at much earlier level cause large lateral distance much below; thus earlier history is now important and the dependence on age follows. In Giller et al. (2015) a simple universal function of only one variable describing the lateral distribution at various ages for electrons with different energies was derived by rescaling the lateral distance.\
The universality of the electron distributions determined so far was used for prediction of the light fluxes emitted by showers, the detection of which is a method for studying high energy cosmic rays ($E_0 