Puzzle 47 - alternate configuration with interceptors on carry, borrow

[sat]

I think this alternate configuration is relevant because

• it’s sometimes faster (needs only one ball) and
• makes it easier to see the counters by having interceptors in the carry or borrow direction of the most significant bit from each of the two registers.

[sat]

@mspencer : one more image for your testing.

[donutcomputer]

Are you sure you are allowed to use interceptors?

[sat]

I know Challenge 47 does not allow interceptors.

That’s why the title contains “alternate configuration”, not “better solution”.

But I don’t think interceptors are against the spirit of the problem.
I hope someone will find this configuration useful for understanding counters.