How to make continous spiral floor

[HeadbuttJ]

I am trying to make a spiral floor. I used model line to draw the outlines and used modify sub-elements to level up one end of the floor. I planned to copy it to every level. But I cannot make the floor continous due to line duplication, I have to make a crack on the floor, but by doing so the stair is not continous. Please find my attached file and video. Any idea? Thanks!

[syman2000]

You have to do half arc and you can do spiral.

[barthbradley]

Do you have Modify Sub-Elements? If so, create half-circle Ramp, use Modify Sub Elements to change the end elevation, and Clipboard Copy/Paste Aligned to Level above and Mirror.  Then select both halve-circles and Clipboard Copy/Paste Aligned to every-other Level.