At Bletchley Juniors Codebreaking Club this week we practised some vexillology i.e. the study of flags. I bought some Harry Potter World theme park maps. I then wrote a sequence of instructions to navigate the way around the theme park. I added North and West coordinates to the maps. I then encoded the locations of various places on the map using flag designs, with colours representing numbers. The children were able to successfully decode the flag colours as map coordinates, then read the coordinates on the map to find the location. I threw in some questions about each location, to extend those children who were Harry Potter fans. The other children enjoyed the combination of flags and maps, and having their first go at reading map coordinates.