The hardest part about doing this piece of artwork was trying to do all the tiny details that are on the turtle. Also I had a hard time making sure the bottom part "the sand" is lower than the part where the turtle is because I wanted the sand to have different levels.
With this art, it was really hard trying to scrape out the excess cardboard that was still remaining when I already took off one layer. Also trying to carve straight lines with and Exacto knife was tricky.
The hardest part of doing this was making sure that when I folded the piece of paper, the "cities" were sticking out to make it look 3D (which you can not really tell in the picture).