Modeling spiral stair by sketching

[mgmueller]

My project has an exterior spiral staircase with a total of 16 risers (finish floor to 9' 6-3/8"), 14 of which are around a central pole in a spiral.  The top two risers are straight and there's a short landing that connects with the floor level.  See plan below:

I have tried to model this with the stair tools that come with Revit, but I don't get the exact result.  I have attempted to sketch the stair, following instructions for boundaries, risers, and stair path, but it doesn't work.  See my screenshots below.

Boundaries in green, risers in black.Height to top is correct, but number of risers is -1.

Is it possible to do what I am trying to do?   If so, what am I missing?  Any help would be appreciated.

[ToanDN]

It can be done by sketching two runs within one within the stair so that you don't run into sketch lines overlapping error.