When confronted with a design or management problem, Barbara Mullenex reaches for the same tool every time: a lined Leuchtturm notebook.

“Sketching and drawing helps bring out my ideas and helps communicate ideas to other people,” says Mullenex, a managing principal at design firm Perkins Eastman in Washington, D.C. “It’s an effective way to work through design problems­—and everything from a table setting for a dinner party to an organizational chart for the office to organizing our summer intern program.”