Human eye visual error and glyph

1. An O in capital letters cannot be a positive circle
2. In the strokes, the horizontal will be more fine
   Otherwise it looks like the horizontal drawing will be thicker (visual error of the human eye)
3. The capital letter O is a little bit bigger than H .
   For the letter to appear to be aligned.
4. The cross section of the Strokes is done in a finer
   To look uniform in thickness
5. The left slash is slightly thinner than the right slash (A)
6. The vertical line to the left of the uppercase M is finer than the right
7. The Italian italic is finer than the Roman traditional.
   This is because the same width of the line, simply tilt the look will be thinner, increase the angle of the nib is more so. When writing a Roman traditional, the nib is roughly 30°, and the nib is 45° when writing an Italian italic.

Reference

Latin font

Human eye visual error and glyph