The Commitment to Recovery

Iron Man (2008)
dir. Jon Favreau

Iron Man 2 (2010)
dir. Jon Favreau

Thanks go to Bryan aka Mugrim for pointing this out: After the events of Iron Man, the alcoholic Tony Stark swaps his circular arc reactor out for a triangular one. He also starts cleaning up his act around this time and accepts responsibility for himself and his actions. 

Why a triangle? What could that mean?

Well there's this:

The Mansion

Eyes Wide Shut (1999)
dir. Stanley Kubrick

Iron Man 2 (2010)
dir. Jon Favreau


EWS cap from Screen Musings, IM2 is, obviously, an IGN grab.