How many plays did Eugene O'Neill write from 1913-1918?

Eugene O'Neill wrote several notable plays between 1913 and 1918, including "Beyond the Horizon" (1918), which won the Pulitzer Prize for Drama. During this period, he also developed other significant works like "The Emperor Jones" (1920) and "The Straw" (1920), but his most productive years were actually just after 1918. Overall, he wrote a handful of influential plays in this timeframe, setting the stage for his later success.