Martin Heidegger wrote about boredom in two texts available in English, in the 1929/30 semester lecture course "The Fundamental Concepts of Metaphysics", and again in the essay "What is Metaphysics?" published in the same year. In the lecture, Heidegger included about 100 pages on boredom, probably the most extensive philosophical treatment ever of the subject. He focused on waiting at railway stations in particular as a major context of boredom. Søren Kierkegaard remarks in "Either/Or" that "patience cannot be depicted" visually, since there is a sense that any immediate moment of life may be fundamentally tedious.