The American artist Richard Serra, now 83, is widely renowned for monumental site-specific sculptures, which he executes in heavy sheets of steel—works like The Matter of Time at the Guggenheim Museum in Bilbao; or Promenade, its vertical rectangles, 14 meters high, positioned under the domed ceiling of the Grand Palais. Many of us, however, are not familiar with another facet of Serra’s practice: drawing. These are not studies for his sculptures but distinct artworks. On paper, and using his preferred medium—black paintstick—Serra experiments with shape, perspective, light, and space. “40 Balls” was curated and designed by the artist himself. The more you look at these rough discs of deep black, the more omniscient they become. —Elena Clavarino