これは ゆゆ式 Advent Calendar 2019 2日目の記事です Featured image is used under CC BY-NC-SA 2.0 license. Trio | Iowa Infrared image with 720nm filter | Neal Wellons | Flickr, December 21, 2008. 11周年記念展の便りを待ちながらここ最近ゆゆ式…