Digital fabrication technologies such as laser cutters have been widely used for supporting prototyping of interactive devices as they are able to work with a wide range of materials. However, the majority of laser cut prototype components are often unable to support interaction or visualisation capabilities within themselves (e.g., functionality embedded within the material). Often materials that are laser cut do not have functional properties aside from serving as enclosures for interactive components. Our work explores how optical properties of clear Perspex material can be exploited to support interaction and visualisation capabilities for interface prototyping. Our proposed fabrication approach demonstrates the potential to support the development of novel displays devices that do not require expensive or complex circuitry and electronics. We produce a light-sensitive button and a seven-segment display which are combined into a wearable watch prototype demo. We also discuss design implications and future direction for this work.