Over stringing or cross stringing is where the Bass strings (in mauve) overlap or cross over the steel strings (in blue)
This is the preferred arrangement as the strings are longer,(being longer they are thinner, this enables the string to sustain longer and produce a purer tone) .
The Bass bridge is located nearer the centre of the sounding board Producing deeper richer tones
Straight stringing or vertical stringing is where all of the strings run vertically and are on the same bridge
This arrangement is not as good as the over stringing, as the Bass bridge is in a dead part of the sounding board and the strings are shorter
Oblique stringing is similar to straight stringing except strings are at a slight angle
This arrangement is slight improvement over the straight stringing as the strings are slightly longer and the Bass bridge is nearer the middle of the sounding board, yet still it is not as efficient as the over stringing.