I experimented a lot with various sizes and shapes of hearts (like fatter or thinner hearts) to actually get bubble wrap hearts that would print an impression of a heart. That's the frustrating part of this craft. Despite it looking really easy, making sure the bubble wrap leaves shape that resembles a heart takes a lot of trial and error. So, there's an easier way to make these cards using a completely different method. I'm going to run through it quickly, but if you have any questions, please leave them in the comments and I can answer them. Cut the cardstock into four pieces, like the method above. Then, cut a rectangular-shaped piece of bubble wrap that's smaller than the cardstock rectangle. Paint the entire rectangular-shaped piece of bubble wrap. Press it onto a piece of the cardstock, push down on it to leave an impression, then remove it. Let the paint dry completely, then cut the cardstock into a heart shape. Glue that heart shape onto another piece of cardstock. You'll get pretty much the same result without getting frustrated over the heart shape.