The crystallographic restriction theorem in its basic form was based on the observation that the rotational symmetries of a crystal are usually limited to 2-fold, 3-fold, 4-fold, and 6-fold. However, quasicrystals can occur with other diffraction pattern symmetries, such as 5-fold; these were not discovered until 1982 by Dan Shechtman.
Dan unconcealed new pattern.
I used synonym for discovered and system couldn't tell.
( z1 person :name ( z2 name :op "Dan" ) )