of the punishment was reserved for Sisyphus due to his hubristic belief that his cleverness surpassed that of Zeus himself. Hades accordingly displayed his own cleverness by enchanting the boulder into rolling away from Sisyphus before he reached the top which ended up consigning Sisyphus to an eternity of useless efforts and unending frustration. Thus, pointless or interminable activities are sometimes described as "Sisyphean". Sisyphus was a common subject for ancient writers and was depicted by the painter Polygnotus on the walls of the Lesche at Delphi. Interpretations According to the solar theory, King Sisyphus is the disk of the sun that rises every day in the east and then sinks into the west. Other scholars regard him as a personification of waves rising and falling, or of the treacherous sea. The 1st-century BC Epicurean philosopher Lucretius interprets the myth of Sisyphus as personifying politicians aspiring for political office who are constantly defeated, with the quest for power, in itself an "empty thing", being likened to rolling the boulder up the hill. Friedrich Welcker suggested that he symbolises the vain struggle of man in the pursuit of knowledge, and Salomon Reinach that his punishment is based on a picture in which Sisyphus was represented rolling a huge stone Acrocorinthus, symbolic of the labour and skill involved in the building of the Sisypheum. Albert Camus, in his 1942 essay The Myth of Sisyphus, saw Sisyphus as personifying the absurdity of human life, but Camus concludes "one must imagine Sisyphus happy" as "The struggle itself towards the heights is enough to fill a man's heart." More recently, J. Nigro Sansonese, building on the work of Georges Dumézil, speculates that the origin of the name "Sisyphus" is onomatopoetic of the continual back-and-forth, susurrant sound ("siss phuss") made by the breath in the nasal passages, situating the mythology of Sisyphus in a far larger context of archaic (see Proto-Indo-European religion) trance-inducing techniques related to breath control. The repetitive inhalation–exhalation cycle is described esoterically in the myth as an up–down motion of Sisyphus and his boulder on a hill. In experiments that test how workers respond when the meaning of their task is diminished, the test condition is referred to as the Sisyphusian condition. The two main conclusions of the experiment are that people work harder when their work seems more meaningful, and that people underestimate the relationship between meaning and motivation. In his book