Do you know how the normal sized humans transformed as Hobbits in the movie The Lord Of The Rings? You too can shrink and grow back as they did 🙂 Because they used several Ames room sets in Shire sequences to make the heights of the diminutively-sized hobbits correct when standing next to the taller Gandalf.
What is an Ames Room? Well before getting into the detailing watch this video by The Royal Institution.
A diagram of the true and apparent position of a person in an Ames room, and the shape of that room
An Ames room is a distorted room that is used to create an optical illusion. Probably influenced by the writings of Hermann Helmholtz, it was invented by American ophthalmologist Adelbert Ames, Jr. in 1934, and constructed in the following year.
An Ames room is constructed so that from the front it appears to be an ordinary cubic-shaped room, with a back wall and two side walls parallel to each other and perpendicular to the horizontally level floor and ceiling. However, this is a trick of perspective and the true shape of the room is trapezoidal: the walls are slanted and the ceiling and floor are at an incline, and the right corner is much closer to the front-positioned observer than the left corner (or vice versa). (See overhead view diagram to the right)
As a result of the optical illusion, a person standing in one corner appears to the observer to be a giant, while a person standing in the other corner appears to be a dwarf. The illusion is so convincing that a person walking back and forth from the left corner to the right corner appears to grow or shrink.
Studies have shown that the illusion can be created without using walls and a ceiling; it is sufficient to create an apparent horizon (which in reality will not be horizontal) against an appropriate background, and the eye relies on the apparent relative height of an object above that horizon.
Courtesy : The Royal Institution via YouTube, Wikipedia