when you use shape(s,0,0); you can use translate (x,y,z); before it to place in 3D.
You can also rotate to let them stand upright
Use with pushMatrix and popMatrix
Where did you download the shapes?
There are also 3D shapes to download
Remark
In my chess program I use images from Wikipedia, showing all pieces and empty squares as well
Remark
By the way When you look at my avatar image you see a 3D chessboard. The pieces are 3D, the design is from the famous Bauhaus Chessboard.