Lars and Nana
Lars Ivarsson is, of course, the son of Sixten, and has arguably surpassed his Father in terms of design and artistry. Nana, benefits from being Lars' daughter, and was never allowed to stamp or sell a pipe until her Father and Grandfather agreed it was up to snuff. I owned that first pipe for over two years, and while Nana has certainly continued to progress, you could see her aesthetic sense even in her earliest work. Lars' work is more masculine and organic, while Nana, I believe, brings an element of delicacy to her pipes. Despite similarities in shape, a keen eye should always be able to differentiate between the two.
