What were the subjects or themes used​

texture , shape , color .

Explanation:

1. red- the color of blood

2. black- the color of the darkness in my soul

3. white- the color of the clouds

4. orange- a fruit

5. blue- the color of water

i think these large heads represent their gods and i do think they were worshiped by the people. if there was only one head and no heads around it i think it would be monotheistic but if there are several heads close to each other it could be polytheistic.