Light sculpture

Seen during an art exhibit, a light sculpture consisting of high-voltage sign tubes, one filled with argon and mercury (blue) and another one with neon (red, with trace amount of argon). It is interesting to note that the combination of neon and mercury lights is whitish due to the combined presence of all primary colors. Such combination was used in lighting applications before the advent of the first commercial hot-cathode fluorescent tube in 1938.