That coat rack
It appeared to me that immediately after Astaire grabbed the coatrack and set it wobbling, that the wobbling was very minor. Later in the "solo" dance, the wobble became more pronounced.
Freeze-framing the DVD during the earlier sequence, I thought I saw dark weights(?) embedded in 4 corners in the underside (underside pretty well hidden) of the circular rack base. Later, those "weights" disappeared. The vertically cross-strengthened base then became much more visible to viewers, leading to more pronounced wobbling, which would enhance Fred's "finale".
Did anyone else notice a change in mobility of that rack as the dance proceeded?
MGM had some talented production designers (Cedric Gibbons?) who could have altered revolving/rotating behavior of Fred's dance partner as dance went on. And, we viewers would never know. Tilt?!
E pluribus unum