Challenge 1: "Write a script to print first 10 Sexy Prime Pairs. Sexy
primes are prime numbers that differ from each other by 6. For example,
the numbers 5 and 11 are both sexy primes, because 11 - 5 = 6. The term
"sexy prime" is a pun stemming from the Latin word for six: sex."

My notes: Clearly defined, yet another prime-based task, sounds very
easy - let's have a go..


Challenge 2: "Write a script to implement Lempel-Ziv-Welch (LZW)
compression algorithm. The script should have method to encode/decode
algorithm. The wiki page
https://en.wikipedia.org/wiki/Lempel%E2%80%93Ziv%E2%80%93Welch
explains the compression algorithm very nicely."

My notes: I read the wiki page, perhaps without concentrating enough.
Looks complicated, especially the decoding part.  Also, what's not
quite clear is what initial alphabet both encoding and decoding should
use?  but let's have a go, hopefully building an encoder will clarify
most things?