Charlie Mucke is using HDPE (High Density Polyethylene) such as plastic bottle lids to highlight the issue that plastic is one of most common materials affecting the health of the Earth. It gets into our oceans and damages the ecosystem, along with pollutants being put into the air because of its production.
The pattern in the plastic takes on the form of a satellite view from different areas of the Earth. The holes that are present in the plastic symbolises the areas of the Earth that we are losing due to human actions such as animals becoming extinct and global warming causing the ice caps to melt.
Charlie has chosen a pebble shape which is an organic shape as she is showing that some of the world problems can be solved, but they take time and patience. Just like a pebble, it begins life as a rough stone being tumbled around, but ends up becoming a smooth, less jagged shape that symbolises calmness. She also like the use of a simple shape so as not to deter away from the colours that have been used within her pieces.