Answer - Bowling Optical Illusion
The mind constantly takes two dimensional images it sees and converts the data into a map of reality, which is three dimensional. In this optical illusion, we see the pins on the wall as being way down at the end of the bowling alley, so they must be larger. The closer pin also sits next to a bowling ball to give a reference to its size. The bowling ball way down the alley is used as a reference for the size of the pins on the wall, making them seem larger.