A “twisted heart” is the feeling of unrequited love, falling in love with someone but never having that love returned.
Might as well occupy your hands while you're feeling sorry for yourself.
See here for video: https://youtu.be/-wHls7r-QTs
The two halves of the heart twist apart easily, but getting them back together is harder than it looks!
There are two versions. The “Twisted Heart Ring Box” is 100mm across and contains a hidden compartment. The “Twisted Heart Puzzle” is 75mm across, it uses less material but does not have a hidden compartment.
Twisted Heart Ring Box: https://than.gs/m/997532 Twisted Heart Puzzle: https://than.gs/m/997533