In typography letters based on the circle or part circle are usually described as having either oblique or vertical stress, or shading.
If we borrow from the terminology of the compass, letters with oblique stress may be described as having the thickest parts of the strokes at points approximately North-East and South-West. The 60 point Bembo characters shown below will make this point dear and figure (b) on page 200 shows how such round forms are made with a broad-nibbed pen.
We use the term approximately because the position of the thickest parts of the strokes in these round letters with oblique stress will vary not only from type to type but may do so within the range of a single lower-case alphabet. For instance, while the lower-case e may conform perfectly to our description of a letter with oblique stress and therefore NE/SW shading, the o from the same alphabet may be very nearly vertical in stress. To illustrate this we print below examples of the original 60 point Caslon Old Face (Founders).
Again while certain lower-case characters conform to the definition of letters having oblique stress or shading the capitals of the same fount may be letters having an almost vertical stress.
Letters with vertical stress or shading have the thickest parts of the strokes due East & West. The letters shown below are set in 60 point Bodoni (Monotype