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We keep the interface simple as much as we can while leaving some hints for users to explore themselves. http://courses.csail.mit.edu/6.831/wiki/index.php?title=Image:Liuhuan-design-click.JPG http://courses.csail.mit.edu/6.831/wiki/index.php?title=Image:Liuhuan-design-profile-action.JPG http://courses.csail.mit.edu/6.831/wiki/index.php?title=Image:Liuhuan-design-filter-and-others.JPG 
Youtube style project page
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This story board illustrates part of the functionalities mentioned in scenario one using the second design. http://courses.csail.mit.edu/6.831/wiki/index.php?title=Image:Storyboard.001.jpg http://courses.csail.mit.edu/6.831/wiki/index.php?title=Image:Storyboard.002.jpg http://courses.csail.mit.edu/6.831/wiki/index.php?title=Image:Storyboard.003.jpg http://courses.csail.mit.edu/6.831/wiki/index.php?title=Image:Storyboard.004.jpg http://courses.csail.mit.edu/6.831/wiki/index.php?title=Image:Storyboard.005.jpg http://courses.csail.mit.edu/6.831/wiki/index.php?title=Image:Storyboard.006.jpg 
The rest of the story is the same as using the filter functionality described in the design section. When user selects a filter, the UI will have the same effects as searching: only matching stars show up in the universe.