Colored Dot On Bottom Of Beer Can Why Is There A Dot On The Bottom Of Every Beverage Can?

Why is there a dot on the bottom of every beverage can? - colored dot on bottom of beer can

I realized that there is a point at the end of each first beer can, but recently I saw a can of Coke and is no different. Why are small colored dots on the underside of the box, and what do they mean?