The floors, in the Capitol, are terrazzo tile from Italy. Apparently, 66 Italian artisans were hired to lay the floors. Each of them had a blue tile to be used as a signature piece. They were free to place them wherever they wished as they worked. Only 55 of these tiles have ever been found. It's believed that the others have been covered by interior walls or carpeting.
The nice lady at the information desk told me about the tiles and showed me this blue one.
South Dakota State Capitol
Pierre, South Dakota