As a player I love Mold Earth. I would love to share my opinion on the spell. I love to use it to dig tunnels, build defensive walls, to blockade cave entrance with dirt, etc. But I never try to do anything that I (a person in real life) wouldn't be able to do with a simple shovel just in much longer period of time. I would be happy if other players in my game do the same. This way we avoid
questions like this one
As a rules lawyer I also believe "You cause shapes, colors, or both to appear
on the dirt" refers to making a 2d pictures.
i.e. you can magically do in 6 seconds the same thing that you would be able to do with a stick and some talent in the same dirt just in a bit longer time