Light bulbs.

Undoubtedly!! No wonder this great photograph of yours was selected by the Editors. It is very creative and appealing, captivating. Relatively young photographers may not know this, but this evokes the good old times of classical-school photography of the 60s through 80s, when photography had much less technical resources, and therefore, creativity played a greater role, like in this case. Superb image, truly. Sincere congratulations on it's conception and brilliant execution.

DG