With the current fashion of curvaceous buildings, the need to shed light on solar glare is becoming an increasingly important design consideration. London's "Walkie Talkie" skyscraper is the latest to reflect "death rays" that partially melted a car and almost set fire to a barbershop's entrance.

As Londoners basked in an uncharacteristically sunny summer day, the concave elevation of the incomplete 37-floor building at 20 Fenchurch St. focused solar rays onto the opposite sidewalk, melting part of a Jaguar's roof and scorching barber Re-Style's doormat. The building, designed by New York City-based Rafael Viñoly Architects, is the firm's second project to catch heat. In 2010, a sunbather on the pool deck of the 57-story Vdara building in Las Vegas complained of extreme burns and a melted shopping bag.

The London building's co-developers, locally based Land Securities Group plc and Canary Wharf Group plc, have acknowledged responsibility, erecting a screen to help cut the glare. The design team previously had undertaken extensive analysis of reflections from the facade, including checking on glare on the street below, claims a developer's spokesman.

"At no stage did that multiple modeling suggest that there was going to be an issue with light reflecting and focusing at ground level," says the spokesman. However, some factors "are almost impossible to predict with the [current] tools of analysis," adds a developer's statement.