There are very many possible shapes:
a square based pyramid
a triangular prism
a square anti-prism
a cuboctahedron
a rhombicuboctahedron
and possibly more.
See link for images.
Pyramid
square
Cube
Cylinder
Pascal's triangle was invented by Blaise Pascal (1623-1662) in 1653. Although it has been named after blaise pascal, there have been traces of the triangle, long before Blaise Pascal was born. It is belived that the Persians and the Chinese had been using it to find the square and cube root of numbers. Whoever asked this question is a complete idiot, because the answer is in the question.
Where were the traces of the past found
You didn't say if you wanted it used as a noun or a verb so here are two sentences.There were no traces of the criminal.When he traces the picture, he always adds something to it.
Where were the traces of the past found
Traces of Catastrophe was created in 1998.
Human Traces was created in 2005.
Traces of Red was created in 1992.
Traces of Smoke was created in 1992.