AppleInsider notes that at this time it is not clear why Apple is countersuing S3 Graphics. The details of their complaint, filed this month, remain unknown. Apple's complaint in a US District Court in the Northern District of California is currently classified as an "oversized document," which means that no one can download it (yet) to find out what it contains. The countersuit does appear to be related to patents. However, it is not currently clear whether Apple is accusing S3 Graphics of patent violations itself, or if Apple is seeking to invalidate the patents S3 is suing it for violating.