Fastest way do a spiral stair.

 From:  danperk (SBEECH)
11084.23 
Hi Anthony,

After I read your comments I checked and apparently I'm still using 15 year old software from 2008 (Adobe Acrobat 9 Pro Extended).
Time flies when you're having fun.

If you have an Android phone/device, 3D PDF Reader (Tech Soft 3D), has worked pretty well for me. Not sure about iOS, as I don't have it.