Foldit uses ABEGO coloring as a guide to how well the backbone angles of a segment correspond to "ideal" angles. (See also Ideal Loops.) ABEGO coloring appears in several spots. The protein can be shown in ABEGO colors by selecting the "AbegoColor" option available under "Color" on the "View" menu. (This option requires that the "Show advanced GUI" option be checked under "General Options".) The sequence shown in the Blueprint tool can optionally be shown in ABEGO colors. The letters have the following meanings and color assignments in Foldit: G - left-handed helix (rare), green in ABEGO coloring