Spiral Staircases

Now   enter your enclosed stairwell and select the brushes
that  have  sealed  off your entrance.  Use the z-axis window
to  raise the offending brushes so that they allow access to
the first step.  Repeat the process on the opposite side with
the top of the stairwell.


   

Now  with  the  top  step  you can simply lengthen the brush so
that it can connect with a second room or whatever.  That's it!

    

This  is just  one  way to create this commonly used structure
but  seems  to  be  the  fastest  way  to  bust one out.  Enclosing
a spiral staircase can be acheived  in a variety of ways but be
sure to do it.  Flying off a stairwell repeatedly during a match
can really piss players off.  Craft your map with love . . . .