I have found an interesting alpha blending feature

. Look how *outlines* of the glyphs appear in the 3ʳᵈ screenshot. Accidental? I like it even then.
I would have thought that inversing twice would have made the glyphs disappear since
Code:
-o , --overlay Don't draw background pixels, and compute foreground pixel color based on the inverse of the underlying framebufer pixel.
BTW dont get fooled by the overlays on horizontal lines, these are not black, they are
Code:
hr {
border: white;
background-color: #992211;
height: 6px
}