By changing your view, you will see different 2D shapes.
Orthographic Projections - Miter Line
The miter line is a construction line that begins at the upper-right corner of the front view and extends indefinitely at a 45 degree angle.
Orthographic Projection - Hidden Lines
A hidden line is a dashed line that shows a feature or surface that is hidden within that view's vantage point, but necessary to help the viewer more easily visualize the 3-dimensional object when all views are considered.