This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Keywords from Image Description:
Helical Gears. This is composite image made from my own photographs of gears from Meccano Set Note that the gears do not mesh in the parallel example it is for illustration only en Arthur Clarke en Arthur Clarke original upload log page en HelicalGears Arthur Clarke bytes no is composite image made from my own photographs