130 To change the background colour requires three control codes. Suppose that you want blue letters on a yellow background then you must use the following sequence of control codes 131 Yellow alphanumeric 157 New background 132 Blue alphanumeric 10 MODE 7 20 PRINT CHR$(131);CHR$(157);CHR$(132);"BLUE LETTERS ON YELLOW" As you will gather to change the background colour you must first select letters of the desired colour, then declare a new background and then reselect the colour of the letter.
Note that you cannot have a flashing background, so the following sequence 136 Flash 131 Yellow alphanumeric 157 New background 132 Blue alphanumeric will produce flashing blue letters on a steady yellow background. 10 MODE 7 20 PRINT CHR$(136);CHR$(131);CHR$(157);CHR$(132);"BLUE LETTERS ON YELLOW" Flash is turned off with control code 137 . To produce double height characters It is possible to write characters with double their normal height using control code 141 . Obviously this takes up two of the normal display lines. What is not so obvious is that you must therefore print exactly the same text on two successive lines. Try the following:
10 MODE 7 20 PRINT CHR$(141);"THIS IS DOUBLE HEIGHT" As you will see it only produces the top half of the letters. Add line 30 and it works properly. 10 MODE 7 20 PRINT CHR$(141);"THIS IS DOUBLE HEIGHT" 30 PRINT CHR$(141);"THIS IS DOUBLE HEIGHT"