Describe the pervasive nature of "Jim Crow" laws. How was the system enforced, formally and informally?

Jim Crow laws were laws that led to the systematic segregation and oppression of African Americans in the United States between 1876 and 1965. Jim Crow laws were a series of laws that were created and enforced at the state and local level to segregate and oppress African Americans from receiving access to state resources and institutions like education and others. The system was formally enforced by the police and by the courts. For example African Americans could be disallowed from entering restaurants or were forced to use specific water fountains or could not enter certain schools. The police in the South generally where the laws existed would enforce these laws brutally at times as well as the courts.