A building by Le Corbusier isn t the kind of thing you deface lightly.

The Swiss-French architect was a pioneer of the modernist movement and is renowned for the humanizing touch he brought to crowded cities.

Just last week, UNESCO added 17 of his projects to its list of World Heritage Sites.

So it may surprise you to learn that one of those projects—a building in Marseilles, France called La Cité Radieuse—was recently covered in what look like random bands of red and yellow paint.

In fact, they comprise three optical illusions designed to help you see Le Corbusier s work in a new light.

But move to the right vantage point and the fragments merge into clear, continuous shapes that seem superimposed on the building.

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