This time last year, The Aperiodical featured the fold-and-cut Christmas tree I designed in their Aperiodvent calendar. I designed it to use as a Christmas card. Print out the PDF, write a message on the tree, or decorate it if you like, then fold it following the dashed lines. When the recipient cuts along the solid black line, they will open out a beautiful Christmas tree.
Have a go yourself by printing out the PDF from https://aperiodical.com/2018/12/aperiodvent-day-13-fold-and-cut-christmas-tree/.
Check out the rest of 2018’s Aperiodvent calendar while you’re there.