Exploration tool
First: Make a guess
Try to guess how these four shapes interact. What will happen if you move blue points (they are stuck to rectangle edges)? Does rectangle shape mater?
Guessing is essential ingredient in scientific thought and it is very important that you don't skip this part.
Second: Make the construction
Try to make construction without the help. If you run into difficulties come back and take a look at the video below.
Third: Other ideas
Try to explore all the figures that are displayed above and see if you can come up with your own hypotheses. Can you prove them?
You will need to make your own construction, the one below is just to show general idea.