Every year since we first met, Siobhan and I have bought a single ornament for the Christmas tree, each one different from previous years. Our tradition works like this. Every year, both when putting the tree up and taking it back down, we go through the years one by one, so each ornament is also a reminder of the memories of that part of our lives. Each year we're retracing our entire relationship up to the present day. Gradually, our tree becomes less and less the generic sameness of a uniform decorating style, and more and more a quirky, individual, personalized reflection of us.
This year's ornament is the pictured theobromine molecule. Theobromine is a key component of chocolate. Made With Molecules makes a new ornament each year, and theobromine is from a few years ago. The current year's ornament is zingerone, a compound in ginger, but we didn't like the look of the molecule that much, and I'm not very fond of ginger either. So I originally tried to order last year's ornament, menthol, from a bookmark I had made last year. The proprietress of MWM didn't intend that page to still be available (and has taken it down since), and is actually out of menthol, but she very kindly went through back stock and found a few previous years were still around, so we were able to get theobromine instead.
The theobromine molecule arrived today and is now in a place of honor on the tree, as well as added to the "tour of the ornaments" website I maintain.