The focus of the US courtroom battle between Apple and Samsung shifted to the iPhone's iconic display on Tuesday, as the US company called a former employee and award-winning graphic designer to back up claims that Samsung gadgets look "confusingly similar".
Susan Kare, who from 1982 to 1986 had a hand in designing icons for the original Macintosh computers, scrutinized the home screens of 11 of the Korean firm's phones - including the Galaxy S and Epic 4G - and found the icons and layout to be very similar.
Apple is contending that buyers may confuse Samsung devices with the iPhone, and accuses the Asian firm of copying design and features. Samsung, in turn, has accused Apple of violating Samsung wireless technology patents.
Kare - who is also credited for Microsoft icons such as the "Notepad" and for its deck of "Solitaire" game cards - testified that even she was fooled by a Samsung gadget at a pre-trial meeting.
"There was a big conference table with many phones on it, and some of them were on," said Kare, who followed the late Steve Jobs to his NeXt computer startup in 1986 before starting her own firm. "I could see the screen. I went to pick up the iPhone to make a point about the user interface, and I was holding a Samsung.
"I think of myself as someone who's pretty granular about looking at graphics, and I mistook one for the other."
When it came Samsung's turn to cross-examine Kare, lead attorney Charles Verhoeven - displaying a flash of theatrics - switched on a Samsung phone and asked Kare to tell the jury what she saw: a bright white Samsung logo.
Apple and Samsung are going toe-to-toe in a high-wattage patent dispute, mirroring a fierce battle for industry supremacy between two rivals that control more than half of worldwide smartphone sales.
The trial playing out in downtown San Jose over the summer is one of many disputes between the two around the world that analysts see as partly aimed at retarding the spread of Google's Android, the world's most used mobile software.
Tuesday's testimony focused on the iPhone's familiar front face, with its outsized square icons. Kare pointed to numerous similarities on Samsung phones, including rounded corners, a range of icon styles from retro-plain to stylized, and an evenly spaced grid.
"It is my opinion that the overall collection of graphic features that makes the overall visual impression could be confusing to a consumer," Kare told the packed courtroom.
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The trial has granted Silicon Valley an unprecedented peek behind the curtain of Apple's famously secretive design and marketing machine, and unearthed internal Samsung documents in which the Korean company saw the iPhone as a competitive threat and sought to match it.
On Friday, lawyers showed Apple Vice President Eddy Cue, in a January 2011 email, urging then-Chief Operating Officer Tim Cook to build a mini-iPad because he believed there was a market for a seven-inch tablet. Late co-founder Steve Jobs was receptive to the idea, according to Cue's email, fanning speculation that Apple plans to make a mini-iPad to take on cheaper gadgets from Google and Amazon.
On Monday, Apple trotted out a veteran designer to bolster its claims. Peter Bressler, a college professor with electronics design experience and some 70 patents to his name, analysed Samsung gadgets and the iPhone and iPad and concluded that many were "substantially similar".
Samsung in turn used visuals and real phones to illustrate a plethora of examples - including different curvatures of corners, sides that protrude marginally above the screen, different positions for "lozenge" earpieces, even encircling bezels that are not uniformly thick - where competing phones diverged.