the correct rectangle code

                                    ` This code was downloaded from The Game Creators
                                    ` It is reproduced here with full permission
                                    ` http://www.thegamecreators.com
                                    
                                    `that activates the backdrop
backdrop on
`that activates the manual sync
sync on
`that colors the backdrop black
color backdrop 0

do
`cls <- it doesn't need, because we use snyc at the end of the loop
line 0, 0, 639, 0
line 639,0,639,479
line 639, 479, 0, 479
line 0,479,0,0
`that syncronizes, refreshes the screen
sync
LOOP
`you don't need to say cls, just say sync