This is perhaps more a stylistic point than a theme, but Discipline and Punish reveals Foucault's addiction to contrast and contradiction. From the shocking image at the beginning of the work to the many numbered lists and pairs of terms, the work is structured around a series of conceits and paradoxes. The idea that prison contains its own failure is a good example. Critics have criticized Foucault for what they see as his chronic obscurity, but at least part of the problem comes from his attitude to language and discourse. Discourses are complex structures in which people can become "trapped": perhaps the experience of being trapped inside some of Foucault's more difficult sentences is meant to echo this. Or perhaps, like many French philosophers, he was just fond of linguistic jokes.