SCREEN - a graphics function that reads a character's ASCII value
         or its color from a specified screen location
Syntax
  SCREEN (row,column[,colorflag])
    - row is the row number of the screen location
    - column is the column number of the screen location
    - If colorflag is not used, or has a value of 0, the character's ASCII
      code is returned. Any non-zero numeric value causes the number of
      the color.
 
See Also  <SCREEN STATEMENT>  <ASCII CODE TABLE>  <COLOR>  <PALETTE>