Mashable reminds us that even as Apple iPod sales continue their decline in the face of growing iPhone and iPad sales, Apple continues to redesign and innovate in the product category that essentially revived Apple revolutionized the music industry in the early part of this century.

The seventh-generation iPod nano, in particular, is probably the most frequently redesigned among all of Apple’s products. The latest iteration is smaller than the palm of your hand, but twice as large (or tall) as the previous model. More startling is the fact that the interface for the tiny nano and the new, thinner, but longer iPod touch are completely different.