The red line needs to cross the middle of the black square, as well as through half the ascent of the capital letters and digits, for example the middle horizontal bar of the F or the crossing point of the two diagonals in the letter X. See also bug 452967.
38FGKX
38FGKX
38FGKX
38FGKX
38FGKX
38FGKX