# Challenge 35. I'm confused

Challenge 35. I have a solution that works. It is not their solution. There answer doesn’t seem to work. Am I reading the instructions wrong. My solution includes a crossover piece.

The solution in the book for challenge 35 seems to be correct for me: A blue ball will be intercepted, if the register has an even value (0, 2, 4, 6) and a red one if the registers value is odd (1, 3, 5, 7).
The idea of the setup is to check the first bit only. If it’s a 0 we catch the blue ball, otherwise we flip it an trigger a red ball. This ball will be catched because of the flipped bit.

Although a crossover piece is not a allowed here for a correct solution, you should feel free to play around and experiment with other parts. Nevertheless the restriction of parts is part of the challenge

I hope that helped. Feel free to share your solution.

All the challenges have more than one solution. If your solution works, be happy with that. You can always revisit it any try a different approach next time. Fewer parts etc. It is open-ended.

Thanks! I guess I figured that if they set the board up for the possibility for more numbers. Then they expected us to use them. I will keep this in mind if I find similar challenges in the future. Thanks again.