Why buy a birthday card when you can make one? Design based on my original foldable cube and rectangular prism designs which use a single thin layer as a hinge. Check out http://designmaketeach.com/2013/07/26/foldable-rectangular-prism-visual-tinkercad-tutorial/ for design tips on this construction method. I personalized the card design with an inside inscription. The age of the recipient was positioned so that it could be seen through the heart shaped cutout when the card is folded closed. Tie the card shut with a ribbon or design an 'envelope' to hold the card.
This thing was made with Tinkercad. Edit it online https://www.tinkercad.com/things/2IogSsJWbWc
Text was colored with Sharpie but I could have paused printer and swapped filament mid-print for a two-toned card. Yes, the recipient thought it was awesome.
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