This instance is from Wikipedia and should be reused underneath a CC BY-SA license. They can be sculpted into a variety of shapes during this process, in some cases resulting in deep thumb-print like indentations on their surfaces identified as regmaglypts. From Wikipedia References in periodicals archive ? Sculpted with https://edwinkamds.blogsidea.com/42894838/not-known-details-about-sculpted-md-lakewood