Rectangles and squares
A square or rectangle are the only regular polygons, but many other shapes have two right angles and two parallel lines.
a square and a rectangle
Polygon
There are no parallel sides on a nonagon (nine-sided figure)... Regular shapes with an odd-number of sides have no parallel sides.
Any polygon with 2n sides (n integer) where opposite sides are parallel, will have its opposite angles congruent.
Some shapes have angles and so they are important in defining the shapes. And angles are absolutely critical for angles. They are the very essence of their existence: if it were not for angles then there would be no angles.
If all the sides and all the angles are the same and in the same order, the shapes are congruent.
Both shapes have 4 sides, 4 right angles and 2 parallel pairs of lines.
A rectilinear figure is a polygon such that all its sides meet at right angles. The only convex shapes are a rectangle (or square), but it can also be a concave shape with some interior angles of 270 degrees.
A rectilinear figure is a polygon such that all its sides meet at right angles. The only convex shapes are a rectangle (or square), but it can also be a concave shape with some interior angles of 270 degrees.
Opposite angles do not bisect any shapes.