The big purple blur

The kids were discussing their plans for the future, and Sarah said, "I'm going to live in a red house, and Noah, you're going to live right next door in a blue house.  Mom, when you drive by really fast, it will look like a big purple blur!"  I told her I wouldn't be driving by really fast; I'd be stopping to see my grandchildren.  (You can never plant the seed too early!)