Now examine the path traced out by the red dot. Notice that it starts near the right edge but ends up in the lower left corner - exactly where the blue dot starts. That seems like quite a coincidence, right? Well, there's a little trickery going on here that is key to making this all work. It turns out that the red and blue dots are actually tracing out the same random wiggle path. The trick is that the red dot is tracing out the three-second portion of the path that occurs before time zero. The red dot is tracing out the portion of the path that occurs between minus three seconds and zero. The blue dot is tracing out the portion that occurs between zero and positive three seconds. We are able to access these negative time values of wiggle() by using the seldom-used fifth parameter of wiggle() - time. This parameter works very much like the valueAtTime() method you can use to retrieve a property's value at any given time.
