By using glass as the substrate instead of the typical FR4 material, circuits can be visible from all angles.
Printed circuit boards, or PCBs, are essentially circuits that have been etched onto a piece of substrate material in order to use less space than something using wires and plugs. Commercially, PCBs are opaque, which does not allow anyone to easily observe the traces unless they get extremely close. It was for this reason that Okubo Heavy Industries wanted to build his own transparent version for a better viewing experience.
