These beads are a bit of a pain to make but, they are really cool since the inside is hollow. You make them by making two disk beads side by side but with a gap in between. Then as you build the disks up they will start to cup into each other. When they get on a tiny gap between the two tops of the disks you can seal them off together as one big hollow bead. As you round the bead out in the flame the air that's caught inside will expand and keep the bead from deflating so make sure you don't have any holes in your bead.
P.S. which is your favorite? I really like the one with the hearts on it ♥