Here is the geometrical construction of the Rose. There are several tools you can play with, and I heartily recommend to download ZuL if you are interested in trying them all.
If you just like to gain a bit insight on the board, try using the tool that displays hidden objects. You will see that each arc has a clearly defined centre. Another interesting tool is the one to move an object. You will see that just the right squared point is moveable: this is because the Rose a rigid shape. Also, scroll wheel of your mouse will zoom in/out.
I'll leave you with a nice geometric problem: Let n be the side of the hexagon, what is the area of the Rose? And the area of the inner "hole"?
Created using //www.z-u-l.de C.a.R..