In this dialog box we have four options for all four corners of this rectangle shape so let us discuss them. In the scroll down list of it we have Corner Options. You can also open this dialog box from the Object menu of menu bar. Once you click on it a dialog box of Corner Options will open. Here in the Properties panel we have Corner option so click on it. Here in the scroll down list of this menu you can find Properties panel. If there is no Properties panel in your working screen then you can find it in Window menu. I will open Properties panel for Corner Options which is at the right side of working screen in the panels section.
I will increase stroke width as 2 point so that we can see it clearly.
There is no fill color in this rectangle, it has only stroke.
