The atoms in the sequence may vary for different sidechains. This plot gives information about the secondary structure of the protein. The diagram below indicates the types of structures we get for different pairs. The level curves indicate the number of residues per turn for the corresponding regular structure. All of the structure can be thought of as helices.
Torsion angles on the diamond packing.
The diamond packing is a set of points in space where the carbons of a diamond crystal would lie.