  We inspect the geometry of proteins by identifying their backbones as framed
polygons. We find that the left-handed helix region of the Ramachandran map for
non-glycyl residues corresponds to an isolated and highly localized sector in
the orientation of the $C_\beta$ carbons, when viewed in a Frenet frame that is
centered at the corresponding $C_\alpha$ carbons. We show that this
localization in the orientation persists to $C_\gamma$ and $C_\delta$ carbons.
Furthermore, when we extend our analysis to the neighboring residues we
conclude that the left-handed helix region reflects a very regular and
apparently residue independent collective interplay of at least seven
consecutive amino acids.
