Keystone Compac Unit Walls Shape High School Campus. With state-of-the-art facilities, McKinney Boyd High School in McKinney, TX opened its doors in 2006 after an initial phase of construction established the majority of the school's classrooms, offices, music, athletic and parking accommodations. An extensive grade change running throughout the new school's site required extensive site preparation and development that resulted in more than 20,000 square feet of segmental retaining walls being built on campus during this first phase. Click to read on.