This is made of Plastic bottle caps and plastic bottles cut in half. All you need for the plastic bottle caps is paint, but you can leave them as is.
1 nail, 1 hammer and a fishing line (sometimes you can find it on the beach) On the side of each bottle cap you need to make a hole with the nail if you can not punch it out with your fingers then try a hammer, but make sure that there is a thick wood surface under the bottle cap. With the Plastic Bottles just cut the bottom off and the top. I am trying to come up with more ideas to do with the middle part. Now have you ever notice that the bottom of the plastic bottles almost looks like a Sand Dollar?