This wonderful 1930's hanging fixture by Gerrit Rietveld features three tubes locked by ebonized wooden square blocks suspended from a rectangular black metal ceiling plate. This lamp was originally commissioned by Paul F. Rickmans, designed by Rietveld in 1922 and executed in 1969 Gerard van  de Groenekan, the cabinetmaker of Rietveld.

Made in Netherlands

Reference: 1000 lights,  page 228