[MrForbes]

Not at all! The message is what comes out the other end...and I am still only selecting one of 4 commands, which is what the rules allow.

Note that I specified the message in each case:

For the message "Drive straight", the signal is: 241
For the message "Turn left", the signal is: 134
For the message "Whack ball", the signal is: 423
For the message "Stop", the signal is: 123

I have modified the SIGNAL to be 3 characters, but I have NOT changed the number of MESSAGES. The are still only 4 messages.

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To show you what would be illegal, consider this example of a use of a larger number of coded messages, with a smaller signal:

The message "drive" uses a first digit of 1
The message "turn" uses a first digit of 2
The message "manipulate ball" uses a first digit of 3
The message "stop" uses a first digit of 4.

Now, we get to the illegal part:

For a first digit of 1, the second digit of 1 means "slow"
For a first digit of 1, the second digit of 2 means "medium"
For a first digit of 1, the second digit of 3 means "fast"

For a first digit of 2, the second digit of 1 means "right"
For a first digit of 2, the second digit of 2 means "left"

For a first digit of 3, the second digit of 1 means "pop off overpass"
For a first digit of 3, the second digit of 2 means "pick up"
For a first digit of 3, the second digit of 3 means "drop"

For a first digit of 4, the second digit of 1 means "with manipulator down"
For a first digit of 4, the second digit of 2 means "with manipulator up"

See how in this illegal example, we use only the 4 digits, and the signal is only two characters long, but it is decoded into ten different MESSAGES!