00:00You reach into the 2D world and take off the girl's hat.
00:04Then you flip it around and put it on backward.
00:06Now, if the girl has only ever existed in 2D,
00:10she can move left and right and up and down,
00:12but she can't move forward and backward,
00:15since that's the third dimension.
00:17That means there's no way she could turn her own hat backward.
00:21And no matter how hard she tries, she can't turn it back.
00:25So, by doing it for her,
00:26you're proving that there's an extra dimension as she never knew existed.
