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Design 2: Timeline
Parents create events which they need babysitters for and babysitters specify availability. These are done with sliding bar timelines broken up by day. The sliding bar makes it very easy to specify blocks of time one is needed. Since these are thin, we can stack many of them above each other, and then checking whether someones schedule matches is just a matter of looking down to see if those blocks overlap. This makes checking for compatible times very easy. We also allow sorting by availability or preference, to make it easy to find a match or pick your preferred babysitters. Unfortunately it limits the amount that can be displayed, which is why we have a toggle for which day is displayed. The toggle buttons are partially filled/colored to show roughly how many matches occur on that day. 
Use: Two parents decide they want to take an evening off to see a movie. They decide on their preferred times on Saturday and make an event on Saturday in SitterPlanner. They decide to sort their babysitters by preference, and quickly notice that their two favorites are not available until later in the evening. They could go with one of the other babysitters they trust, but this time, they decided to go to a later showing so their favorite babysitter can watch their daughter.
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