https://creativecommons.org/publicdomain/zero/1.0/https://www.rawpixel.com/image/13979850Edit ImageSaveSaveEditCropCustom TextTwo men are using a plank over a large log as a see-saw; representing the mechanics of levers. Engraving.Original public domain image from Wellcome CollectionMorePublic DomainFree CC0 image for Personal and Business useInfoView CC0 LicenseJPEGSmall JPEG 924 x 1200 px | 300 dpiLarge JPEG 2360 x 3065 px | 300 dpiFree DownloadTwo men are using a plank over a large log as a see-saw; representing the mechanics of levers. Engraving.More