Today I'm showing three mechanical pencils represented as life-size acorns. All are unmarked, likely made in England or America. Circa 1880 - 1895. All move the writing tip section in and out via a twist mechanism. The middle pencil nut features a built in stanhope at it's top.. Think of a stanhope as an optical lens installed on various objects - like a pencil, which displays a group of miniature pictures (typically beach or religious scenes). Measurement lengths are an average 1 3/8 inches closed and 1 1/2 inches ready to write.