Modular Hearts: 9

Akiko Yamanashi designed the cute little boxes featured here. Each box requires two square sheets of paper : one for the left half of the heart and one for the right half.
 
To close the box, carefully insert one half into the other. Open the box by gently reversing that process. There is plenty of room inside this type of heart box for mini-candies or a small jewelry gift. So sweet!