The "Panathanaic Procession" and the way it's sculpted

 British Museum, "Panathanaic Procession," another closer look at the high and low relief, and some details.  At an oblique angle, it is not very convex.  It's almost like a drawing with some sculptural qualities.  Almost like it's kind of squashed flat.  
Another quality is that the flattening out of the heads distorts how the artists rendered the eyes.  They had a hard time making the eyes turn the curve.  If you look at the profile it looks a bit like an eye from the front, placed on the profile. Almost how Egyptian art puts a frontal eye on profile heads.