In the summer of 1990, a thirty-eight-year-old striker came off the bench for Cameroon and scored. Then he did something nobody had seen at a World Cup. Roger Milla ran to the corner flag, put one hand on his stomach, raised the other in the air, and danced. He scored four goals at that tournament and danced after every one. Cameroon became the first African team to reach a quarter-final. But ask anyone what they remember, and they will not describe the goals. They will describe the hips.

A goal lasts a second. The celebration is what travels.

Twenty years later, in the opening match of the first World Cup on African soil, Siphiwe Tshabalala hit a shot into the top corner at Soccer City. What followed is burned into the memory of a continent. Five players lined up on the touchline and moved as one, a rehearsed routine, shoulder to shoulder, grinning. South Africa did not win the tournament. That dance won the day.

In 2002, when Senegal beat France, the world champions, Papa Bouba Diop laid his shirt on the grass by the corner flag and his teammates danced in a circle around it. It looked like a ritual because it was one.

Something important is happening in those moments, and it has to do with who is watching. A World Cup goal is seen by hundreds of millions of people at once. For the few seconds after the ball crosses the line, the scorer owns the largest stage on earth and can say anything at all. African players have used those seconds, again and again, to say where they are from.

This is why the dances that take over the continent keep finding their way onto the pitch. The Gwara Gwara came out of South Africa and ended up on the Grammy stage. Zanku came out of the streets of Lagos, all sharp legwork and stamping feet. Pilolo came out of Ghana. Each began in a club, a yard or a schoolground. Each was eventually performed in front of a stadium by a player who had just scored and had ten seconds to tell the world something.

It works in the other direction too. A dance done at the corner flag on a Saturday is being copied in a playground on Monday, in a city thousands of kilometres from where it was invented. The pitch has become one of the fastest ways for African movement to travel.

There is a lesson in this about how culture spreads. We tend to think it moves through official channels, through labels, broadcasters and campaigns. More often it moves through joy. Nobody instructs a footballer to dance. Nobody pays for the placement. A person is simply happy, in public, in the way their home taught them to be happy.

That is harder to resist than any advertisement. You can ignore a slogan. It is very difficult to ignore a man dancing at a corner flag.

So the next time an African player scores, watch what happens after. The goal goes on the scoresheet. The celebration goes everywhere else.