well they could be perfect, but i guess its unlikely that the designer would really get an incorrect angle here.
so ken could have just consistently overlapped the upper over the next lower in the mid sections and done exactly the same for each of the 5 strakes and then the even staircase would result. (middle bowing out more than the next makes it shorter). a section or 2 would keep it honest for larger discrepancies.ve

so small diffs.