Friday, September 17, 2010

Ambiguous Figures - The Thiery Figure

While in Spain this summer I came across an ambiguous figure now called a Thiery figure. It is clear from the presence of this shape in mosaics from the Roman period on display in Cordoba, the floor of the Giralda in Seville and the back of a bench in the Real Alcazar in Seville that this ambiguous figure has been around for a long time.

Thiery figure in a mosaic from  the Roman period. (Cordoba, Spain)
The ambiguity of the figure allows us to view the square in the center as a face of a cube to its left as well as the face of a cube to the right. Consider the square in the center, and focus on the vertex at the bottom. This vertex is simultaneously the bottom left corner of the cube to the left and the bottom right corner of the cube on the right.

Bench in the Real Alcazar in Seville, Spain.
 The surface of this bench in the Real Alcazar in Seville, Spain is rather weathered, but the tiling on the top part of the bench is another ambiguous shape. In this case, due to the scale, it can make the pattern appear as a collection of elongated blocks all pointing to the upper left, or blocks pointing to your lower right.

This final example comes from the floor of one of the chapels in the Giralda in Seville Spain.

It is again the Thiery figure. Located on the floor it leaves one with the impression one is walking on a collection of cubes. But in this case are the tops of the cubes made of the white faces, or the red ones?

The name - Thiery figure - is said to have been given in 1895 when it was named after the psychologist A. Thiery. The examples here show that the figure has been around a lot longer than that.

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