Two straight lines connected by one curve is the basic horse-shoe shape.
A curved shape does not have any straight lines. In a circle the line curves continually, meaning that the circle is a curved shape.
distortion of a size, shape, distance, or area occurs.
a polygon!
Polygon: A closed shape bounded by straight lines.
It is the total length of its boundary. There is no need for the boundary to be made up of straight lines or even smooth curves. However, fractals do cause problems.
A figure that has 5 straight lines and 3 curves could be a star shape, such as a pentagram, combined with curved elements like arcs or circular segments. For example, you could create a star with five points and add three semi-circular arcs connecting the tips of the star. This combination results in a figure with the specified number of lines and curves.
A shape with 4 straight lines in which there are 2 parallel and 2 unparallel lines is called a Trapezium.
If the shape has three straight lines and no other lines then it has to be a triangle
A polygon.
A shape made up of line segments is a shape with straight lines, or a polygon. for example, a square has straight lines, or is made up of line segments. A circle is not in that category because it has no straight lines, they are curved.
The letters you listed—h, k, o, and x—are unique because they have straight lines and curves, while a, b, c, d, and e consist of curves and no straight lines. However, if you consider the letters in terms of their shapes, all the letters you provided contain curves except for h, k, o, and x, which all can be formed using straight lines. Thus, the riddle highlights the distinction in shape between the letters.
A hexagon