In Mark's early marble making years, back in the 80's, he initially made some of his marbles to mimic the early German handmade marbles that children played with. This one is modeled after the 'clambroth' style of marbles that are highly sought after in vintage collector circles. It's so fun to see the connection to toy marbles with some of these early pieces, where Mark sought to elevate the form to art over play. Pieces like this are HIGHLY collectible, especially as Mark winds down his career here. Signed with circled 'MM', Mark's signature from the early years in the 80's.