Connect them a chain or garland, add string and hang them somewhere, paste one on the front of a homemade Valentine, etc. Looks like a good Valentine Craft!
Craft: Create chains of paper hearts by cutting accordion-folded paper strips. It's just like folding and cutting paper doll chains! Join two or more heart chains together to make longer chains.
this would be cute to let the kids color different the cut outs, hole punch and string. or when their older, leave blank and let people that attend there birthday party write wishes and then they can hang them up in their room.
Here is a tutorial on how to create a boxed geometric heart. Easy DIY great for gift wrapping activities.
These are Crayon Shaving Hearts! Just need some crayons, wax paper and a flat iron.