The Freer and Sackler galleries are encouraging visitors to take a final peek at Do-Ho Suh’s “Staircase-IV” (at left) as its final weekend on display is fast approaching. The translucent red nylon work is a 1:1 scale reproduction of his New York apartment staircase, complete with architectural detailing. The artist says the “work starts from a reflection on space, especially personal space. The space I’m interested in is not only a physical one, but an…