They used a lot of things to make their concerts interesting to watch. They had a round movie screen on the stage. They would show videos on the screen when they played. They also used lighting and lasers in a much fancier way than many bands do. They also had big balloon puppets. The most famous is in the shape of a pig, which first appeared on the cover for their album, "Animals". The pig has since become a symbol of Pink Floyd. Another symbol that reminds people of Pink Floyd is a prism with light shining through it. This was on the cover of "Dark Side of the Moon", one of their most popular albums. The album was released in 1973, and stayed on music charts for a very long time. Millions of people bought it.