Age of the Slow Pixel is one of the periods of the xkcd comic Time, the last in the Pre-expansion Era.
It lasted from frame 125 to 136.
Generally recognized as a period, although some dispute this.
The period starts as Cueball leaves, along with Megan who already left on Frame 89. The zoom out started, but unnoticeable at first, causing a lot of frustration.
I waited a half hour for one darkening pixel — riversong
The quote also inspired a T-shirt.