Answer by periblepsis for Is this the correct way to create a circuit that convert a 7-bit number to either binary or gray code? (digital logic design)

If you look at your own logic block, it's easy to see that it only has four inputs and one output.

So just make a module out of the red-circled portion, like this:

I'll call it GB for now.

Then the 7-bit converter would look like:

Except that the highest order GB can be replaced with a simple XOR, since it's G input doesn't connect to a higher-order bit's stage and the C input can be ignored since it selects the same thing either way:

You were just on the verge of getting there, I suspect.

I haven't tested this as I trust you already did good work before. But it looks correct to me. That said, you shouldn't trust what I write. Verify it.