In his 1919 manual for screenwriters, Ten Million Photoplay Plots, Wycliff Aber Hill provided this taxonomy of possible types of dramatic "situations," first running them down in outline form, then describing each more completely and offering possible variations. Hill, who published more than one aid to struggling "scenarists," positioned himself as an authority on the types of stories that would work well onscreen. 

Advertising Hill's book in a 1922 issue of the Scenario Bulletin Digest ("A Magazine of Information and Instruction for the Photoplaywright"), the manual's publisher, the Feature Photodrama Company, offered hope to screenwriters feeling stuck for inspiration who might be willing to send away for the volume: 

A few hours' study of this remarkable treatise ought to make it an easy matter to find a cure for your "sick script"; to inject new "pep" and suspense into your story or safely carry it past a "blind alley"; it gives you all the possible information an inspiring [sic] scenarist may require.

Historians Ben Brewster and Lea Jacobs point out that Hill's book was part of a tradition, citing 19^th-century playwriting manuals that likewise listed catalogs of "situations" that could provoke action and frame a plot. Nor was Hill the only screenwriter to publish a list of this type around this time; Frederick Palmers, whose Photoplay Plot Encyclopedia (1922) can be read on the Internet Archive, gathered 36 situations instead of 37.