How to deal with continous staircase with seating, landing, and slope (31.4 KB)

I find a picture which show staircase follows the form of two curves, I did a straight one, I just want to know how to deal with the curve one, I have tried the morph logic, but it’s not the quality which the picture shows. If someone could show some logic? Thanks.

Thanks, Michael, maybe I could make it out combining the definition with tweencurve.