Contributor: Stas Fainer
This is a simulation of the image perceived with our eyes, when looking from the side at a partially submerged pencil in a glass of water. The discontinuity of the refractive index between air and water causes the pencil to appear both broken and bent. However, in this simulation, the breaking is more pronounced. You can check the Bent Pencil simulation where the bending of the pencil is more pronounced.