Learn Spanish (Latin America): ¿Las niñas andan esculpiendo una muralla detallada? - Are the girls going around sculpting a detailed rampart?

Using están esculpiendo just states a fact: they are currently sculpting right now. By using andan esculpiendo (andar + gerund), the sentence emphasizes that the action is scattered, intermittent, or happening over a period of time without a strict trajectory. It translates perfectly to 'going around sculpting'.

Does andan mean the girls are literally walking around while they sculpt?

Not necessarily. While andar literally means 'to walk', in this progressive structure it acts as an auxiliary verb and mostly loses its literal meaning. It simply describes the diffuse or ongoing nature of the sculpting. They could be sitting in one place but working on different sections of the rampart off and on.

Why is the word muralla used here instead of pared or muro?

Pared generally refers to an interior wall of a room or building, and muro is a standard exterior freestanding wall (like a brick wall in a garden). Muralla specifically refers to a massive, defensive wall or rampart, like a castle's outer fortifications or the Great Wall of China (La Gran Muralla).

Could this sentence imply that the speaker is surprised by what the girls are doing?

Yes! Using andar + gerund in a question often carries a conversational undertone of curiosity, mild surprise, or even suspicion. The speaker might be wondering what in the world the girls are up to by building a rampart.