Jack Dorsey's Square, which may just make old-school registers obsolete with their Square Card Readers, Square Registers and Card Cases, is HQ-ed in the  San Francisco Chronicle Building on 5th and Mission. In what some might say is a changing of the guard, the start up's original 10 employees set up shop in the Chronicle's Human Resources floor in December of 2009.

Square's now at more than 100 employees, and just expanded their office another 13,000 square feet into the adjacent wing of the Chronicle Building (their total office space is now 26,000 square feet). California Home+Design's first installment of CH+D Office Space takes you inside Square's new digs, which were designed by San Francisco design and architecture firm Studio O+A. Check it out here.