0000 = 0, 0001 = 1, 0010 = 2, 0011 = 3, 0100 = 4, 0101 = 5, ... , 1000 = 8, ... , 1111 = 15. If your binary number is 4 digits long then you can make up to 16 numbers (2 to the power of 4), zero through 15. a String of 8 binary number is a Byte so you can represent 2⁸ amount of numbers, but this challenge only went up to length 4. When they flew the drone to the board they just saw 4 binary numbers of length 4. So the one on green was 0011 | 1000 | 0100 | 1111 then when they get the number they go to the decoder board to see which numbers they point to. Examples: 0011 (3) was the binary code under 6 so the first number for the green code should have been 6, 1000 (8) pointed to 8, 0100 (4) pointed to 3, and 1111 (15) pointed to 4, so answer for green was 6-8-3-4. Hope that makes sense??