### Triangle Completion - Seeing what is not there!

These two figures shown above rather strikingly illustrate the mind's willingness to see an equilateral triangle despite the fact that no border information about the center triangle is in the picture.
The figure on the left retains only the slightest trace of the vertices of the center triangle but you can probably still "see" the center triangle.
In the figure on the right, we have retained the outlines of the vertices of each equilateral triangle, but introduced some space between where these vertices intersect each other. You may still "see" the triangles in this case, but the effect is not striking.
Here the information about the join of the vertices has been destroyed; lessening the effect even more.
In the final figure on the right all of the lines have been joined, allowing one to parse the picture as a star. When this is done the two triangles are not perceived. However, you may find that you can still see one or the other.

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© Charles F. Schmidt