Continuity: In the beginning scenes, where Milo Thatch is practicing his proposal, he slides over (face forward, chest against the board) a chalk drawing of a map detailing the location of Atlantis. When he realizes he wiped off the drawing, and sees it on his clothes, he stands in front of the blank part of the chalkboard, "filling in" the space with the map that rubbed off on his shirt -- the only problem is, that the image should have rubbed off BACKWARDS as he was FACING the board when it transferred to his clothes. He could not simply stand in the place of the missing map face forward and have it read properly.
