- A translucent blob is shown on the world map.
- 10 flags represent 5 capitals that lie inside the blob, and 5 that lie outside.
- The game start with 5 random flags in the Inside box and 5 in the Outside box.
- Click a flag to select it, then click one in the OTHER boxes to swap them.
- Keep swapping flags between Inside and Outside until every flag is in the correct box.