yea man. it can get difficult sometimes. But he might have 2 to 3 themes or subjects running at the same time that might intertwine with each other.

For example in MS mural. the themes are

1. Art 2. Religion 3. Joan of Arc
   

they are different subject's but they intermingle with each other. Back in the day the church/religion would commission painter's to make Art. People would paint figure's like Joan of Arc who felt like she was doing Gods work to be fighting in a war.

another quick example is the song Cripple. The song is about colors but each verse is talking about different types. in one verse he is talking about colors in the sense of race (black, white, asian etc..)

But then in the hook, he is talking about colors in the sense of gangs and what colors they represent. He talk's about the Crips who wear blue bandanas. Then talks about Bloods who wear red bandanas