Vanishing foam to stop cheating in football

If you've been enjoying the World Cup matches, you've likely seen a new addition to the referee's arsenal: a sprayon foam. If you're not a soccer expert, you've probably wondered where it came from. When a foul is committed outside the penalty area, a free kick is given.

The opposing team must stand at least 10 yards away from the spot where the foul was committed. In the past, referees estimated the distance visually or measured it out precisely.

Now for the first time in a FIFA World Cup, referees are marking the spot of the kick and the 10 yard minimum.

Referees mark these spots with a foam called 9.15 Fair Play, a vanishing spray that disappears minutes after use. It was developed by an Argentine journalist, Pablo C Silva, who dubbed the spray '9.15' because of its conversion from yards to meters.

Silva invented it because in an amateur league in Argentina, he was consistently watching opposing players encroach on his precious 10 yards. His patented spray is chosen to debut at this World Cup.