  Story ideation is a critical part of the story-writing process. It is
challenging to support computationally due to its exploratory and subjective
nature. Tropes, which are recurring narrative elements across stories, are
essential in stories as they shape the structure of narratives and our
understanding of them. In this paper, we propose to use tropes as an
intermediate representation of stories to approach story ideation. We present
TaleStream, a canvas system that uses tropes as building blocks of stories
while providing steerable suggestions of story ideas in the form of tropes. Our
trope suggestion methods leverage data from the tvtropes.org wiki. We find that
97% of the time, trope suggestions generated by our methods provide better
story ideation materials than random tropes. Our system evaluation suggests
that TaleStream can support writers' creative flow and greatly facilitates
story development. Tropes, as a rich lexicon of narratives with available
examples, play a key role in TaleStream and hold promise for story-creation
support systems.
