Galang and his friends are planning a craft project for the school bazaar. Monita suggests making wall decorations in the shape of fish using plastic bottle caps. The bottle caps are used as the fish's head and body, with toy eyes and a tail made from triangular paper. They attach them to blue paper and add plant ornaments made from green paper. Andre also has an idea to use used plastic bottles and pipes as craft materials. However, Made argues that used pipes are hard to find at home. They agree to try Monita and Andre's ideas.
What is the main topic of the conversation?