To me, as long as we’ve known each other, I’ve always thought Mick’s most brilliant thing was that he could work in an area two foot square and give a very exciting performance.

Richards is praising Mick Jagger’s stagecraft in terms of economy and control: Jagger doesn’t need elaborate choreography or a huge physical range to command attention. The “two foot square” image suggests a performer who can concentrate energy, timing, facial expression, and micro-movements into a small space and still generate excitement—an implicit contrast to rock frontmen who rely on constant motion or spectacle. Coming from Jagger’s long-time bandmate and sometimes rival, the remark also reads as a grudgingly affectionate acknowledgment of a complementary skill within the Rolling Stones: Richards as the anchoring guitarist, Jagger as the kinetic focal point who can make even minimal movement feel charged.