This page was made with a simple drag and drop action script. It has 6 different dinosaurs and 10 different plants on top of the page. When the user clicks each of them, it will jump directly into the frame of its correct period. After that, the user can drag it around within its frame.
Another part is the names of these three periods. The user will see a hint which is an image of mouse cursor. The user need to click on it, and it will show the names of sample dinosaurs and sample plants in the period.