The view looking through flat glass is generally expected to be crystal clear by the viewer. However, occasionally the view looks a little off. It might be warped or wavy. If it is, that’s an example of glass distortion. Glass gets distorted in a few different ways, most of which are during the manufacturing process, such as when heat-strengthened or tempered flat glass is being made. When the molten glass is spread, it can start to droop between the rollers that move it along the system. These small dips are then locked in place during the cooling process, creating what is known as roller wave distortion in the glass.