Galileo’s Telescope.Binocular

This optical device was a long hollow stick, at one end of which a bicon-like lens was installed, and on the other - two-way. Despite the inconspicuous appearance, it gave a 3-fold increase and allowed to see a very clear picture. High quality image (of course, by the standards of that time) was achieved due to multiple and thorough grinding of lenses. And although Galilee's visual tube is outdated, this optical scheme is still used in theatrical binoculars.