While Hal was spending time with Dewey, they both built a city out of things like blocks, Hal describes what they have built is like Utopia.

The city has many tall buildings, like sky scrapers and also has rides like ferris wheels, there are also lights hanging from the celling of the house with planes.  

Dewey soon becomes mad with power, ( At one point when Hal says that they both built the city, Dewy claimes that he was the one who built the city) he soon decides to build an army of identical figures ( They all wear white clothes). there are also tanks with Dewey's men. 

At one point it seems that Deweys men are on top of the city buildings surrounding Hal, but Hal just picks up Dewey and walks away with him, seconds later Lois comes in to the house and trips over a part of the city, causing her to fall on to the city and destroying it all first she crushes a house with person and a car then she knocks over the sky crapers then she falls over the table crushing all the toy soliders and tanks before fianlly destroy in the ferris wheel , in slow motion, as Hal and Dewey watch.

Later during Malcolm's play, Dewey is seen with one of his men in his pocket.