The Four Color Theorem is a famous mathematical theorem that states that no more than four colors are required to color the regions of any map so that no two adjacent regions have the same color. Adjacent means that two regions share a common boundary curve segment, not merely a corner where three or more regions meet. Unlike other proofs before its discovery, computers were used to resolve this long-standing mathematical conjecture that was first proposed in 1850 by Francis Guthrie. After more than a century later, mathematicians, Kenneth Appel and Wolfgang Haken, finally derived its proof in 1976, and determined that it is practicality impossible for humans to verify it without the use of a computer. According to the four color theorem, a ...