In case you didn't see it, tonight the Brewers had a bit of a stolen base/hit and run on with Carlos Gomez on first base. He never slowed and took third when the ball was fielded and thrown to first for the out. The ball was then thrown to third to try and get Gomez out, but was overthrown and Gomez came home on the error.
If not, Disciples of Uecker broke down the play with diagrams to analyze the Cubs' defense of the situation. Check it out here.