This lamp is designed to hold a 4 inch (10 cm) solar replacement light. It’s design was influenced by the tall buildings in Chicago. When the solar light (in the on position) is placed in front of a window that gets direct sunlight, the lamp will light at dusk the same as an outdoor solar light.
Here is a link to the light I used in the lamp and the wood filament (affiliate link). The wood varieties I used were Cherry, Teak, and Walnut.