Contribute correction: MSX GRAPH-SCAN

  _____     _____    __   __   _    _   
 / ____||  |  ___||  \ \\/ // | || | || 
/ //---`'  | ||__     \   //  | || | || 
\ \\___    | ||__     / . \\  | \\_/ || 
 \_____||  |_____||  /_//\_\\  \____//  
  `----`   `-----`   `-`  --`   `---`