dinate of the centre of the graphics screen. Also accessible via the American English spelling <code>GRAPHICS_CENTER_X</code>.</li>
<li>**<code>GRAPHICS_CENTRE_Y</code>** – An integer containing the Y coordinate of the centre of the graphics screen. Also accessible via the American English spelling <code>GRAPHICS_CENTER_Y</code>.</li>
<li>**<code>PI#</code>** – A real constant for π (<code>3.141592653589793238</code>). <br  />
 Useful for trigonometric or geometric calculations.</li>
<li>**<code>E#</co