Dependence of the average step coordinates on the backbone substates of the same step. The two backbone fragments of the step can be both in BI (BI/BI, continuous lines) or one of them in BI and the other in BII (mixed, BI/BII, broken line) or both in BII (BII/BII). The BI/BII state implies higher twist and slide and lower roll compared to BI/BI. It also increases rise (particularly in CG steps) and the absolute value of tilt and shift. The BII/BII states are rare, but in steps where there are enough of them, they imply even larger changes following the same trends (not shown). Only the values for the WW end states are plotted; the TT values show the same trends.