I found a set of these glass tumblers and the design is very interesting. The bottoms are slightly heavy and the weight varies with each glass. The amber color of the glass looks like Nuutajarvi glass, but I can't be sure. I seem to recall seeing this design on a website somewhere, but I can't figure out which one it was. Could these possibly be Kaj Franck's design? Any help or suggestions would be hugely appreciated.