Apple design secrets exposed How Apple came up with the 6th gen iPod Nano and the iPod Shuffle

So how did Apple get from the 4th/5th gen iPod Nano to the device's current form factor? Well, it was actually a complex process with multiple objectives

Source:
http://www.edibleapple.com/apple-design-secrets-exposed-how-apple-came-up-with-the-6th-gen-ipod-nano-and-the-ipod-shuffle-photo/