A lighting system is described. One embodiment of the lighting system includes a light guide, a first lighting device, and a second lighting device. The light guide receives light along a transmission interface. The first lighting device has a first plurality of lighting elements coupled to a first substrate between a first pair of reflector walls. The first substrate and the first pair of reflector walls define a first exposed side of the first lighting device. The second lighting device has a second plurality of lighting elements coupled to a second substrate between a second pair of reflector walls. The second substrate and the second pair of reflector walls define a second exposed side of the second lighting device configured to match the first exposed side of the first lighting device. Using lighting devices without sidewalls illuminates a diffusion panel so that there are no dark spots.