A display unit has a base with a base plate, a set of reflectors and a transparent or translucent cover. The base plate has an array of openings. Each opening is sized to receive a light socket from a string of lights and hold the light socket. There is one reflector for each opening in the base plate positioned adjacent a respective opening in the base plate and against the front surface of the base plate. A transparent or translucent cover is positioned over the set of reflectors and connected to the base. Two or more display units can be connected together side by side, parallel or at an angle to one another to create displays having different heights, different widths, and different shapes. The user can easily create letters, numbers, symbols, icons or pictures through the choice and positioning of lights having different colors in the display units.

A hazard triangle includes a triangular shaped body formed of a transparent or semi-transparent material having a thickness and three sides, one of which is a proximal edge. The thickness is substantially less than a length of any of the three sides. An illumination element is configured to emit light into the proximal edge. The emitted light is propagated by the body such that light is emitted from surfaces of the body other than the proximal edge.

A hazard triangle includes a triangular shaped body formed of a transparent or semi-transparent material having a thickness and three sides, one of which is a proximal edge. The thickness is substantially less than a length of any of the three sides. An illumination element is configured to emit light into the proximal edge. The emitted light is propagated by the body such that light is emitted from surfaces of the body other than the proximal edge.

A holder for supporting electrified inserts that may vary in width, comprises a base having a groove into which the insert can be placed. Two or more gaskets can be positioned in the groove with each gasket including a resilient section adapted to engage the insert so as to retain the insert securely in place within the groove. Each of the gaskets also includes an electrical conductor, such as an electrical wire, which may be embedded in the gasket, in a position where it makes electrical contact with the electrical terminals on the insert.