##Entity positioning
##entity position horizontal
##Use the 'pos' attribute to manually adjust spacing between entities. By default each entity is spaced apart by one unit of distance. This can be modified by the 'pos' attribute, e.g., -0.25 means that the entity is only spaced by 0.75 units of distance from the previous one. The unit of distance defaults to 130 pixels and can be scaled by the hscale chart option.
A, B [pos=-0.25], C [pos=+0.25], D;
A->B-C-D;