This instance is from Wikipedia and should be reused below a CC BY-SA license. They are often sculpted into various designs for the duration of this process, at times leading to deep thumb-print like indentations on their own surfaces known as regmaglypts. From Wikipedia This example is from Wikipedia and https://sculptedmdlakewood94836.bcbloggers.com/35498663/the-ultimate-guide-to-sculpted-md-lakewood