As in the following image, we can see how the default sketch does look like. "Top" view, of course.
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But, as I mentioned, we may accidentally move the mouse, while holding the buttons, and orientation is "lost", so to speak. The reason is, sketch mode, by default, does not have a fixed orientation. Same situation is within other software.
So, if you got your self in the situation as in the image below:
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all you have to do is to go to the Sketch menu, and select "View sketch".
>> Sketch -> View Sketch
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Or, simply click the same icon, which is available on the toolbar.
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