Forum - What are the three types of public forums?

The right to free speech and assembly guaranteed by the First Amendment could seem different depending on where the speaker choose to have their speech. The three categories of forums were established by the Supreme Court in the case of Perry Educ. Ass'n v. Perry Educators' Ass'n, 460 U.S. 37 (1983): nonpublic forums, designated forums, and regular public forums.