During the past week, it seemed that Apple had its way with Samsung, presenting large documents as proof that Samsung copied its designs and infringed on its patents. But this week it’s Samsung’s turn to go on the offensive against Apple. The company accuses the iPhone maker of infringing three of its patents, and also of ripping off multitouch from other products, even though Apple (Steve Jobs himself actually) claimed that it invented the technology.

One of Samsung’s patents that Samsung claimed Apple is infringing is the process of seamlessly emailing photos. Samsung used Dr. Woodward Yang, an electrical engineering professor at Harvard, as a witness to testify about this, and prove how Apple infringed that patent.

However, when questioned by an Apple attorney, Yang couldn’t say whether Samsung has used that technology in its own smartphones. I’m not sure if that matters though, since only the existence of the patent is necessary for “patent infringement” to happen.

Later, Samsung questioned designer Jeeyuen Wang, who said she and a large Korean team worked three months on the app icons for the Galaxy S phone: “I slept perhaps two hours, or three hours a night,” Wang said. Apple then showed her the documents in which the Galaxy S was being compared to the iPhone, but later Wang said that some of those documents were done well after they finished the designs for the Galaxy S.

Samsung also presented evidence that multitouch technology was being used long before Apple said it “invented” it, demonstrating prior art against Apple’s patents, and asking the Court to invalidate Apple’s claims. Here’s the video that was showed:

And here’s another video showing how Steve Jobs himself said Apple invented multi-touch, when he announced the original iPhone: