This happened to me once.
polriver plays a Throne Room.
... and plays a Throne Room.
... ... and plays a Bridge.
... ... ... getting +1 buy, +$1, and reducing all costs by $1.
... ... and plays the Bridge again.
... ... ... getting +1 buy, +$1, and reducing all costs by $1.
... and plays the Throne Room again.
... ... and plays a Smugglers.
... ... ... gaining a Province.
... ... and plays the Smugglers again.
... ... ... gaining a Province.