The SVG <rect> element defines a rectangle. The <rect> element has the following attributes:
x and y attributes are respectively x- and y-axis coordinates of the top-left corner of the rectangle
If the attributes are not specified, the value is '0'.
width and height attributes define the size for the rectangle. These attributes can not be
negative - it is an error. If you set a value of zero it will disables rendering of the rectangle.
rx and ry attributes are respectively x- and y-axis radius of the ellipse used
to round off the corners of the rectangle. If the value is set only for one of these attributes, the other attribute is counted as
equal to the specified value. If neither rx nor ry is specified the rectangle will not be rounded.