Topic addressed during lunch with Etienne Mineur in a nice italian restaurant.

Or... the intriguing settings of the numeric keypads on the iPhone.

Yes "keypads" is plural because there are two layouts:

The dial layout: "1 2 3" in the lower segment.
The calculator layout: "1 2 3" in the upper segment.

Why two layouts? For a reason I explained here already: this basic interface evolved from two different culture, which are the calculators culture (started with Felt and Tarrant’s Comptometer) and the telephone keypad.

Why do I blog this? What we have here is a tremendously interesting example of an interface clash between two design cultures. It's highly intriguing to see that it has not been made more cohesive. Perhaps both layouts are so sticky that it would be weird to unify them? Who's ready to change that?