splityarn calls this the "Easiest Knitted Sweater Zipper Install Ever" and it looks like it might be. I haven't tried it yet but I'll let you know if I do - my one attempt to put a zipper into a knitted sweater came out OK, but not this nice.
Determine remaining daylight on your hand. Use this simple trick to measure the remaining daylight without a watch. Count the finger widths between the sun and the horizon. Each finger is equivalent to 15 minutes, with each hand totaling an hour.