Pull / Pulk Revolving Doors

There are barn doors
And there are revolving doors

Doors on the rudders of big ships
We are revolving doors

There are doors that open by themselves
There are sliding doors
And there are secret doors

There are doors that lock
And doors that don't

There are doors that let you in
And out
But never open
But they are trapdoors
That you can't come back from