Rainbow flag Alliance (ICA) designed an international co-op symbol and a flag for the first "Co-operators' Day," which was held in July 1923. After some experiments with different designs, a famous French cooperator, Professor Charles Gide, suggested using the seven colours of the rainbow for the flag. He pointed out that the rainbow symbolized unity in diversity and the power of light, enlightenment and progress. The first co-op rainbow flag was completed in 1924 and was adopted as an official symbol of the international cooperative movement in 1925. In 2001, the ICA's official flag was changed from a rainbow flag to a
Rainbow or several narrow, faintly coloured bands can be seen bordering the violet edge of a rainbow; i.e., inside the primary bow or, much more rarely, outside the secondary. These extra bands are called "supernumerary rainbows" or "supernumerary bands"; together with the rainbow itself the phenomenon is also known as a "stacker rainbow". The supernumerary bows are slightly detached from the main bow, become successively fainter along with their distance from it, and have pastel colours (consisting mainly of pink, purple and green hues) rather than the usual spectrum pattern. The effect becomes apparent when water droplets are involved that have