Okay, I think this is fairly obvious, but you may not agree!? This is near the end, when the two burglars are actually trying to get into the house. Joe Pesci is walking up the ice-covered front stairs and he actually makes it up (finally!). Just as he is about to place his hand on the door handle, we notice a big honkin' "M" on the knob, "M" for McCallister. Kevin has strategically place a RED HOT somethin' or other on the inside so that Pesci will cook his hand. The direction in which he places his hand on the knob indicates that the impression of the "M" would be sideways, however, when he removes his hand and we see it smokin' it is rightside up, and I am sorry, but that is a definite mistake, with a capital M! Happy movie-watching!