Herz lists the Diamond Square Square as Caro & Fils (2SQDI) in his Collectors Guide... but Robt. Eisenstadt's mold project index has listed a "Code and Co.". http://www.antiquegamblingchips.com/molddesign_geometric.htm
We'll have to have him check Code/Caro when he gets back from The Big Show. Curious about CARO mold also!