 You could have a lot of fun with optical illusions. Without even realizing it, we're always looking for information to help us sense our location. A lot of this information is visual, but our eyes can easily be fooled. Hey! Are you squishing my head? Okay, try this. Look at this picture. Which of these bars is longer? The upper bar? Actually, they're both the same length, but the lines that intersect them create the false illusion of depth. That the bar on the top is further away. Just like when we look at railroad tracks. We know that each railway tie is the same length, but objects always look smaller when they are further away. So grab your friends, add a camera, and get creative staging your own optical illusions. Not on the railroad tracks. Experiment, having people stand closer and farther away. You can make your friends look really big, or really little. Or you can lean on large objects. Have fun and see what kinds of convincing illusions you can create.