My friend wanted me to design a keychain for our mutual friend who is Canadian and whom she calls her "little maple leaf". I included the design both with and without the heart. If you would like it two-sided, duplicate the .stl and mirror one of them (this is an option in Cura), and then glue them together. I added a post-processing command in Cura to pause at layer height to switch out the filament.

Note: I had to enable the option "Fill Gaps Between Walls: Everywhere" in order to get the outline to print without gaps.