Maybe “re-defining” is too strong a term- its raises expectations. One expects a strong, deliberate deviation from the norm. A statement. A space like no other.
No- the example below is not a re-definition of public space. It is perhaps a different expression of it…yes that is the term. EXPRESSION.

A construction zone on a street…expressing itself (courtesy of Le Pain Quotidien) as a public zone.

View from sidewalk

Interesting detail of floor structure- Place it anywhere and Voila!..instant decking for public space!