In the opening scene of the movie the two main characters get involved in rolling dice for the map to El Dorado. The dice are white and they win the throw, only to be accused of using loaded dice, which are red!
If you watch, the guys that they are playing against, tell them that instead of using the red dice that the two main characters have to play with their dice which are the white ones. Miguel and Tullio have red dice, and the group of guys they are playing against have white dice.
Tsk, tsk, tsk. You do realize that after the fat dude was examining the RED dice, the soldiers came, then the 2 guys, (I don't know their names) PICKED up the dice, and then started FIGHTING! PS. I forgot to mention, they might have dropped the red dice, then the fat dude picked them up. OTHERWISE...