Christa Mrgan has published an interesting post at Rogue Amoeba about developing the look and feel of that company's Piezo recording software. Rogue Amoeba is known for simple, intelligent designs. It's fascinating to see how the company works from beginning to end, first defining the app's functions, then wireframing and prototyping to get everything right.
The article describes the influences that went into Piezo's look and feel, from the sublime (Piezo's look was inspired by a beautiful old audio unit) to the practical (a handle on the square icon). It's interesting to see Rogue Amoeba's commitment to making something special.