This implies that in most cases a Fischer projection is not an accurate representation of the actual 3D configuration of a molecule. It can be regarded as a projection of a modified version of the molecule, ideally twisted at multiple levels along its backbone. For instance, an open-chain molecule of D-glucose rotated so that the horizontal bonds with C2 are slanted toward the viewer, would have the bonds with C3 and C5 slanted away from the viewer, and hence its accurate projection would not coincide with a Fischer projection. For a more accurate representation of an open-chain molecule, a Natta projection may be used.