Diagram of a triangle with a right angle and a left angle

Drawing of a man in a coat

Man standing on top of a rock next to a body of water

Black and white drawing of a boat with a tree in the middle

Black and white drawing of a tetrahedron

Piece of paper with Chinese writing on it

Molecular model of a peptide molecule with a white background

Black and white drawing of a machine with a ruler on it

Black and white drawing of a set of tools