FASTERMIND (1K ZX80 and 16K ZX81)
by D C Owen
from ZX Computing 2, August/September 1982, page 118

This version of Mastermind (a trade name owned by Invicta), uses the letters A
to F. The first program is for the ZX80, and the second for the ZX81.

As you'll see when you run the program, a correct letter in the wrong position
will give a" + ", while a correct letter in the correct place gives a "*". You
are, of course, trying to get four *'s in as short a number of guesses as
possible. Note that letters may be repeated within the code. Invalid guesses
are rejected.

[There is a bug in the program that results in a 'out of screen' error report 5
when the game is won. This is resolved by the addition of the following line:

   495 SCROLL
]