1) The painting "The Scream" by Edvard Munch is an iconic work of art that depicts a figure in anguish and has become a symbol of existential angst.

2) The word "book" contains two vowels: O and O.

3) The Federal Reserve System, often referred to as the Fed, is the central banking system of the United States.

4) The word "triangle" contains four vowels: I, A, E, and E.