A classroom activity to have students encoding and decoding data is to look at the Semaphore flag system. The teacher would start by discussing what the Semaphore flag system is and why it was created (history). Students would then make their own set of Semaphore flags using coloured paper cut and stuck together, or white paper coloured in yellow and red. The flag handles could be made using lengths of wooden dowels, glued and rolled one side of the paper. Working in pairs or small groups, students would spend some time familiarising themselves with the Semaphore flag system, then spelling an animal name. Students then take turns to use the Semaphore flag system to spell the name of the animal they practised, and their partner or group has to decode and guess the animal name.