The Tangle confronts the reader with a variety of links without providing sufficient clues to guide the reader's choice. Tangles can be used purely for their value as intellectual amusement, but also appear in more serious roles. In particular, tangles can help intentionally disorient readers in order to make them more receptive to a new argument or an unexpected conclusion .
On entering a hypertext, a tangle can lead visitors to different entry points, helping to convey the breadth of a hypertext to readers who may not anticipate the hypertext's scope or coverage. The home page of designer David Siegel , for example, opens with four identical icons that lead to four different "home pages" -- each offering a different design and a different emphasis. New or infrequent visitors must choose arbitrarily, and thus will likely see different parts of the site on each visit .
Readers may, through habit or preconception, form an excessively narrow view of a hypertext. Because tangles are difficult to fit into a simple, preconceived structure, they encourage browsing and discovery. Tangles may extend through many writing spaces  or, like Siegel's entryway, may be limited to a single Montage. Tangles are frequently encountered near the beginning of a hypertext, where they disrupt orientation and create a sense of depth, but Carolyn Guyer's Quibbling  places a maze at the center of the hypertext, forming a bridge between scenes or episodes. Tangles may be used as pacing devices, or to recapitulate moments or pathways encountered earlier in a reading. Tangles are often found within or adjacent to Mirrorworlds.
Moulthrop terms hypertexts robotic when the logic of the hypertext, not reader choice, tends to dictate the course of a reading . Robotic tangles like Mary-Kim Arnold's "Lust"  combine complex dynamic structure, rich in broken cycles and other structural cues, with a dearth of interactive choice. This structure serves to entice the reader while frustrating the quest for release and resolution.
Sieves sort readers through one or more layers of choice in order to direct them to sections or episodes. Sieves are often trees, but may be multitrees, DAGs, or nearly-hierarchical graphs; different topologies may all serve the same rhetorical function.
Where the choice is informed and instrumental, sieves become decision trees. The Yahoo directory, for example, provides a large sieve that readers traverse to find topical entry points to the Web. Sieves need not be represented as explicit hierarchies; the Hot Sauce MCF browser displays sieves in three-dimensional space and permits readers to "fly" in SemNet style through the sieve to their destinations, whereas the Hypertext Hotel  hides its introductory Sieve behind a check-in desk and hotel lobby.
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