The two great subjects of Etel Adnan’s paintings are a mountain in California and the Mediterranean Sea. For the past six decades, she has returned to them again and again, playing with the endless possibilities that color, texture, and a palette knife lend to her diminutive geometric abstractions of a peak and a horizon line. The most whimsical thing about her recent exhibition in Beirut, however, was neither Mount Tamalpais in Marin County nor the curve of the Levantine coastline. Rather, it was the way the sun and the moon slipped into those familiar landscapes and then seemed to follow