"Skizze." . . . . . . . . "The exceptionally simple theory of sketching. Why do professional sketches look beautiful?" . "The exceptionally simple theory of sketching. Why do professional sketches look beautiful?"@en . . "Anleitung" . "The exceptionally simple theory of sketching : why do professional sketches look beautiful?"@en . "The exceptionally simple theory of sketching : why do professional sketches look beautiful?" . . . . . . . . . "The exceptionally simple theory of sketching : Why do professional sketches look beautiful?" . "Technische tekeningen." . . "Zeichnen." . .