Confession of a Dangerous Mind - poisoned cup scene (Sam Rockwell & Julia Roberts)

First, Patricia put some poison in Chuck's cup, a weird shaped sugar cube and had the spout for the cream face inwards. Then, while Patricia was looking out, Chuck put the sugar cube on Patricia's saucer and faced the cream spout outwards. He didn't switch the cups. And then, while Chuck was looking at the picture on the wall, Patricia turned the entire tray around, putting the poisoned cup on her side, putting the sugar cube on her own plate. He fake bluffed her in the first place. she double bluffed to nothing. End result: Patricia got poisoned, and Chuck kills the mole.