We made these ice cubes the other day using whatever we had lying around. We got our some small containers and filled them with different colored water. Then we added all sorts of bits and pieces. I added the yarn so we could hold them up. We stuck them outside for the afternoon and then checked on them in the morning. The kids were super excited to see what the cold had created..."just like the freezer," T said. Good observation! Especially since it is in the negative digits where we live! We put them in a bowl and watched them melt.