The 'flag with squares' that can be seen in the work is a Wiphala flag, a symbol of the indigenous people of the central Andes and the Bolivian Amazon rainforest.
I consulted Wikipedia:
The symbol consists of seven by seven squares in seven colours, with each square having the colour of the plane that is on the top left or bottom right. The colour of the longest diagonal line (seven squares) determines which of the four suyus (regions) the flag symbolises: white for Collasuyu, yellow for Kuntisuyu, red for Cinchaysuyu and green for Antisuyu.
The flag here therefore appears to be that of the Kuntisuyu region.
There is also an alternative pattern for the wiphala of Antinsuyu. The rebel movement of Túpac Katari also had its own wiphala. The meaning of the colors is as follows:
* red: earth and the people of the Andes
* orange: community and culture
* yellow: energy
* white: time
* green: natural resources
* blue: heaven
* purple: Andean governance and self-determination
Bolivian President Evo Morales proposed incorporating elements of the Wiphala into the Bolivian flag.