A parade of familiar faces made their way through the courtroom today as Apple and Samsung finished up their rebuttal cases, with the last few hours consisting of expert upon expert saying the other was wrong. Apple, however, may have struck gold in taking out some of Samsung's strongest arguments against tap-to-zoom and bounce-back patents.

The day started off with a light touch, spirits no doubt buoyed by the knowledge that this would be the last day of testimony. Judge Lucy Koh made a passing joke about yesterday's "crack" comment; Apple attorney William Lee stepped forward in response. He'd received an email from his 86-year-old mother last night, he said, asking what crack was and wanting to make sure he wasn't into anything bad.

Susan Kare returned to the stand later in the morning to discuss testimony from one of Samsung's designer. The company's argument has been that many of the its design choices were made out of necessity, and that usability dictated their selection. Kare disagreed, saying there were multiple design choices the company could have made — and didn't.

Bressler ran into troubles again

Things took on a greater sense of urgency in the afternoon as Apple tried to power through multiple witnesses in its remaining time. Peter Bressler, who had a difficult time under cross-examination last week, took on Itay Sherman's assertions that the iPhone and iPad designs aren't original. Looking at several examples of claimed prior art, Bressler drew fine distinctions that he said differentiated Apple's designs, even using the public response to the iPhone as proof of originality.

"In my experience, a design doesn't have that kind of impact unless it's truly unique," he said — only to run into trouble yet again when questioned by Samsung's attorneys. Charles Verhoeven asked Bressler whether Apple owned the concept of rounded corners or a black rectangle, repeatedly driving home the argument the company has been making from the beginning: Apple's designs are common sense and shouldn't be protected.

A good day for bounce-back

Karan Singh and Ravin Balakrishnan made two of the biggest impressions, however — and may have helped hand Apple a victory on its bounce-back and tap-to-zoom patents in the process. Samsung has argued that bounce-back was obvious largely due to the DiamondTouch Table application Tablecloth, which features similar functionality, while suggesting LaunchTile's "semantic zooming" is analogous to tap-to-zoom. The Tablecloth argument has been particularly compelling, but Apple's witnesses erased many of the questions surround the two patents using a combination of source code and common-sense demonstrations. It was revealed that Tablecloth's code refers to two distinct images rather than a single document — a critical distinction given the language of Apple's utility patent. Revisiting LaunchTile made it very clear just how different the software's zoom mode, which essentially jumps into a single-window app view, is from Apple's magnification-only feature.

Apple rest with 16 minutes left.

What's a mode?

Samsung had just 37 minutes on the clock, and began by calling Dr. David Teece. Tim Williams followed, with both men defending the validity of Samsung's UMTS standards-essential patents from Apple's attacks. Dr. Woodward Yang returned to discuss the issue of modes. The differentiation between a mode, a device state, and even an app has become crucial to Samsung's accusations of infringement, with the company arguing that modes and iPhone apps are alike for the purposes of the trial. Yang addressed two of Samsung's utility patents, arguing that Apple's hair-splitting over modes didn't apply with regard to the company's photo-bookmarking patent, while also refuting Apple's defense that the iOS software infrastructure puts it in the clear for the background music playback patent.

Yang then took on Apple's invalidity arguments over the '460 patent, which covers emailing photos and image browsing. The examples Apple used, Yang said, didn't describe the same functionality — and therefore shouldn't take Samsung's patent out of play.

With the clock at zero, Samsung was then officially out of time.

Done with one minute left

Apple used its last five minutes on the clock to question Yang. Attorney William Lee called back to a trial document in which Samsung was supposed to list all of its own devices that use the utility patents referenced in the trial. For two of them, Samsung listed not a single device. Yang explained it was only a partial document, and before going any further into the back-and-forth, Lee finished up — with one minute left out of the 25 hours each side started with.

Jury instructions will be discussed Monday, with closing arguments scheduled for Tuesday. Should all go to plan, the jury will begin deliberations on Wednesday — and that's when the real fun begins.