Parametric spiral stair

Hi all,
Is there anyone who could help/advice me t

o model this staircase please?

  1. Turn History on.
  2. Make a block which represents one step of the stairs.
  3. Use Plane command to make rectangular planar surface. This surface represents flattened staircase.
  4. Array the block along the planar surface.
  5. Make curves which represent side edges of the staircase.
  6. Use Sweep2 command to fit a surface through the curves.
  7. Use FlowAlongSrf command to draw the staircase.

Now you can change the input of the FlowAlongSrf command because you have turned History on.