In geometry figures can be devised so that an illusion is created. M.C Escher (1898-1971), an artist known for his complicated optical illusions, created the "Waterfall" in 1961.
Careful inspection of the figure draws attention to the perception that water can flow uphill.
Even though the tower on the left is one story taller than the tower on the right, the two appear to have the same height.
Escher's works often have the observer question his reasoning .