The mini animated LED Christmas Tree is small 32 x 32 PCB with 8 LED flash you will do in the order you want, you use the Arduino software and Core13 library that allows to program the ATtiny13 with lce software, then it is easy to make a mini greeting card and incorporate the Tree and the CR2032 3 Volts button.
Step 1: How to Make Mini 32x32mm 8 LED Christmas Tree Whith ATtiny13 Soic Version
the attached pdf shows you how to create and test LED figures, test visually, and save them with the TREE8LED software. create a mini Christmas tree with PCB KiCad software (similar to Eagle and free) program the ATtiny13 with the Arduino software 1.06 or 1.64. all useful links are at the end of PDF
Step 2: VIDEO of Christmas Tree
I put all of my files attached instructable in part, some PDFs are French but you can do a copy / paste in google translation
You can see a video of Tiny Christmas Tree illuminated at this link: