The 620 Series. #621 This 24 by 34 inch plaque in the Electrical Engineering Office of the University of Colorado Engineering School is dedicated to a student who was killed in a climbing accident in the Rocky Mountains. Material: glass and flagstone. #622 Jarrow Montessori School uses this for acknowledging significant donors to the school. With a flagstone background, the triangular panels above the copper logo are removable for engraving. Additional panels can be added at a later date. #623 Made as a centerpiece in a Unitarian Church, this marble, flagstone and brass sculpture is 28 by 28 inches.