Penrose triangle
{'<entity_0>': 'impossible object', '<entity_1>': 'Oscar Reutersvärd', '<entity_2>': 'Penrose triangle', '<entity_3>': 'Lionel Penrose', '<entity_4>': 'Penrose tribar', '<entity_5>': 'Roger Penrose', '<entity_6>': '1934'}
[['Penrose triangle', 'discoverer or inventor', 'Oscar Reutersvärd'], ['Oscar Reutersvärd', 'point in time', '1934'], ['Penrose triangle', 'discoverer or inventor', 'Roger Penrose'], ['Penrose triangle', 'discoverer or inventor', 'Lionel Penrose'], ['Penrose triangle', 'named after', 'Lionel Penrose'], ['Penrose triangle', 'time of discovery or invention', '1934'], ['Penrose triangle', 'named after', 'Roger Penrose'], ['Penrose triangle', 'subclass of', 'impossible object'], ['Penrose triangle', 'instance of', 'impossible object'], ['Penrose triangle', 'alternative', 'Penrose tribar'], ['Penrose triangle', 'start time', '1934'], ['Penrose triangle', 'description', 'impossible object']]
The <entity_2>, also known as the <entity_4> or the impossible tribar, is a triangular <entity_0>, an optical illusion consisting of an object which can be depicted in a perspective drawing, but cannot exist as a solid object. It was first created by the Swedish artist <entity_1> in <entity_6>. Independently from Reutersvärd, the triangle was devised and popularized in the 1950s by psychiatrist <entity_3> and his son, prominent Nobel Prize-winning mathematician Sir <entity_5>, who described it as "impossibility in its purest form". The term "<entity_2>" can refer to the 2-dimensional depiction or the <entity_0> itself.
['impossible object']