Some art begs to be touched. Other pieces want to be sat on, like Vito Acconci’s public-art benches at the airport and Scott Burton’s stone seating in Battery Park City. Now, along comes Tim Eads’ viewer-powered butter churn and toast maker—public art with an incentive. You, the viewer, sit on the piece and pedal, and as a reward for your hard work you eat warm toast with fresh butter.