“What is irreplaceable to you?” Capturing diverse answers from the local community, a public art installation now graces Dohm Alley, near the corner of Nassau and Witherspoon Streets. The Princeton University Humanities Council and the Arts Council of Princeton (ACP) are co-hosting the exhibit that runs through October. It features portraits and stories arranged by ACP Artist-in-Residence Robin Resch, a Princeton-based photographer who earned her Master’s in Architecture from Princeton University in 2003.