Presidential libraries were signed into law in 1955 and have since been prized commissions. The Guardian US Opinion asked Dattner Architects and three other firms to sketch unofficial proposals for President Barack Obama’s Library; proposals that would go beyond traditional form and program. Each designer took one of the proposed sites, with Richard Dattner choosing a University of Chicago location between Jackson Park and Lake Michigan. The spiral structure sits lightly in the park on piloti, allowing the park to flow freely around and through it. Envisioned as a sustainable facility, it features a green roof with outdoor terraces, expanses of glass for natural daylight, and light sensitive spaces and programs located based on solar orientation. While President Obama still has two years to go, it’s never too early to get a head start.