"The Island Euleria sank over the course of a year.
A helicopter captured 11 photographs of the top of the island. It took a picture every time the island had sunk three feet, and one of the island before it sank.
The biggest hills on the island are thirty feet tall.
Sketch a picture of the island."
So I'm thinking that I can represent the island as $z=f(x,y)$.
Then, each photograph is a cross section, $f(x,y)=c$
So these photographs, overlayed, is just a contour map?
Also, in the second-to-last photograph (27 feet submerged), there are three tiny circles. Does that represent where the hills are, because in the photos before that, the circles were bigger and bigger, which I think means that the hills were slowly being submerged.
Question: Am I interpreting this correctly?