The simple circle—a head, the moon—is among every child’s first achievements in drawing. It is also a symbol of eternity and infinity. What happens when a circle meets a grid, and is then irradiated with spectral colors? Curves and crosses, geometries and orbits, Op art intensities that recall Buddhist mandalas and Indian Tantra drawing: Welcome to the world of Field Kallop. The mysticism inherent in Kallop’s mathematically structured canvases—a sort of music of the spheres—places her in the company of Hilma af Klint and Emma Kunz. Don’t miss “Circles.” —Laura Jacobs