Lately, Johnson draws for pleasure, but for three decades she had a happily hectic career as an illustrator, sometimes presenting clients with dozens of sketches a day. Her playful watercolors once adorned packages of Lotus software; for a program called Magellan, she created a ship whose masts were tethered to billowing diskettes. She made a popular postcard of two red parachutes tied together, forming a heart; several other cards were sold for years at MOMA’s gift shop. Johnson produced half a dozen covers for this magazine, including one, from 1985, that presented a sunny vision of an artist’s life: a loft cluttered with pastel canvases, each of them depicting a fragment of the skyline that is framed by a picture window. It’s as if the paintings were jigsaw pieces, and the city a puzzle being solved. Now Johnson is obsessed with making puzzles. Many times a day, she uses her grids as foundations for elaborate arrangements of letters on a page—word searches by way of Mondrian. For all the dedication that goes into her puzzles, however, they are confounding creations: very few are complete. She is assembling one of the world’s largest bodies of unfinished art.