I wanted to comment on the aspect ratio of the Duo’s outer and inner screens – both about 1.4 : 1. As an ex-graphic designer, this ratio (known as the silver ratio, 1 to the square root of 2) is very well known to me. That is because in the UK and Europe all our paper sizes are based on this ratio.
A4 is 297 x 210mm which when folded exactly in half results in A5, which has the same ratio. This continues with smaller sizes of A6, etc. Going the other way, A3 is double A4, etc, until you get to A0, which has a surface area of 1 metre squared. Neat eh?
The iPhone Duo therefore is like an A5 sheet of paper, folded in half when closed, and is something that will have been very familiar with Molly Anderson who (like Jony Ive) is from the UK.
Stuart G. via email
I don’t know about you, but I prefer referring to the iPhone Duo’s shape as the “silver ratio” instead of “passport style.” It’s catchy and classy. And it’s cool to know that Apple put some serious thought into the form factor and not just arbitrarily picking a shape.
The iPhone Duo was introduced during the “Surprise and Shine” event on September 9. Apple will start taking orders for the iPhone Duo on October 16, and shipments start on October 23. Learn more about the iPhone Duo.



