You will need to print:
6 x heart.stl (2 x Red, 2 x Yellow, 2 x Green)
2 x border-2-2.stl (with two holes)
1 x border-2-1.stl (with one hole)
I used SBS and PETG plastic on clear glass and some glue.
It is better to print 100% infill if you have semitransparent plastic like me.
In bottom heart you may place some metal spacer to add some weight.