Thanks for the reply. I'm pretty unfamiliar with what that bit of math is though. Most of the solutions involved some formula that has me puzzled.

For better description clarity I'd word:

given 2 strings show concatenation of:

• the reverse of the 2nd string with inverted case; e.g Fish -> HSIf

• a separator in between both strings: @@@

• 1st string reversed with inverted case and then mirrored; e.g Water -> RETAwwATER

I did notice that pattern for the first few examples, because you set
them from a-d, cool.

And so for the rest, I'm thinking okay I'm going to use the letters of the
alphabet. Say you want G to be the goose, then I'd arrange a-g # of elements, but
that can't be it because in one test Z is 10.
Am I subtracting 10 from 26,
so when say I start at Q and count 10 I get Z back?

Thanks for your time.

It wasn't clear to me how
5 returns a.name
12 = b.name
20= z.name
30= z.name
etc. can someone please enlighten my slow @Sz :/