This is a concept design for a mobile phone that only - get this - calls people! (I am waiting for the day that a phone comes out with no voice connectivity.) This looks to us like a great, simplistic design. The photo here is a revision of the original design used to better portray the functionality.

The 3.14″ phone has basically 5 buttons, 4 to dial and one to answer. The 4 buttons with numbers allow you to dial by sliding them to the left, pushing on the center, or sliding to the right on each button to get the corresponding numbers. The top button that looks like it doubles as the speaker is used to answer. Push it once and the transparent display pops out to make a call, or to check caller ID. When receiving calls you push it again to answer. When you are done you simply close the straight-edge to hang up.

Cool.

Source [ProductDesignForums]