The power and beauty of energy- and angle-resolved two-electron emissi
on in the double photoionization of atoms is demonstrated, concentrati
ng on the particular shapes of the angular correlation patterns of the
triple differential cross section. The cases selected are direct doub
le photoionization in helium and neon as well as sequential double pho
toionization in xenon, both for equal and unequal energies of the emit
ted electrons.