When Professor J. Meejin Yoon designed the memorial for Sean Collier, the MIT police officer killed in the line of duty in April 2013, she used granite—32 massive chunks of it—as a symbol of strength and a nod to the New Hampshire mountains that Collier liked to climb with the MIT Outing Club. Constructed using both historic stone-setting principles and robotic fabrication technologies, the 190-ton memorial forms the shape of an open hand to represent Collier’s service and generosity. Its five walls join at a central keystone, embodying strength through unity; the open space beneath it suggests his absence. Rob Rogers, one of Collier’s brothers, served as a project manager for the memorial’s construction, and a quotation from his eulogy is engraved along one granite wall: “Live long like he would. Big hearts, big smiles, big service, all love.”