How the Ford Mustang built a future on its past

Remaking an iconic car poses both great opportunity and great risks to auto designers, who have to balance corporate pressures, demands from customers and their own visual intelligence. Here's a look at how Ford designers worked through dozens of sketches and models for the fifth-generation Mustang, the "retrofuturistic" version that came out in 2005, and the many blind alleys that led to the successful final vehicle.