Density of states mapping for C (in the diamond structure), Si, Ge and β-Tin (data from the entries Si1_ICSD_652255, Ge1_ICSD_181071, C1_ICSD_52054 and Sn1_ICSD_53789 in AFLOWLIB). In all the panels, the top row shows the MIDI velocity mapping of the density of states values in shades of color (gray=0, red=127); the middle row shows the density of states data and the bottom row the mapping of the energies on the 88 keys of the piano (MIDI notes 21 through 108).