NOTE: for challenges, use "!" exclamation point

ruby ghost01.rb 
How many players? 
2
numplayers = 2
New word to pick
Player 0 pick a letter
Letter? 
a
Current word: ["a"], string: a

Player 1 pick a letter
Letter? 
b
Current word: ["a", "b"], string: ab

Player 0 pick a letter
Letter? 
d
Current word: ["a", "b", "d"], string: abd

Player 1 pick a letter
Letter? 
u
Current word: ["a", "b", "d", "u"], string: abdu

Player 0 pick a letter
Letter? 
c
Current word: ["a", "b", "d", "u", "c"], string: abduc

Player 1 pick a letter
Letter? 
c
Current word: ["a", "b", "d", "u", "c", "c"], string: abducc

No initial matches
Player 0 pick a letter
Letter? 
!
Current word: abducc
abducc not found

Challenge issued, player 1 has ["G"], all players: [[], ["G"]]

New word to pick
Player 1 pick a letter
Letter? 
a
Current word: ["a"], string: a

Player 0 pick a letter
Letter? 
b
Current word: ["a", "b"], string: ab

Player 1 pick a letter
Letter? 
a
Current word: ["a", "b", "a"], string: aba

Player 0 pick a letter
Letter? 
c
Current word: ["a", "b", "a", "c"], string: abac

Player 1 pick a letter
Letter? 
k
Current word: ["a", "b", "a", "c", "k"], string: aback

Player 0 pick a letter
Letter? 
!
Current word: aback

Challenge issued, player 1 has ["G", "H"], all players: [[], ["G", "H"]]

New word to pick
Player 1 pick a letter
Letter? 
a
Current word: ["a"], string: a

Player 0 pick a letter
Letter? 
b
Current word: ["a", "b"], string: ab

Player 1 pick a letter
Letter? 
a
Current word: ["a", "b", "a"], string: aba

Player 0 pick a letter
Letter? 
c
Current word: ["a", "b", "a", "c"], string: abac

Player 1 pick a letter
Letter? 
c
Current word: ["a", "b", "a", "c", "c"], string: abacc

No initial matches
Player 0 pick a letter
Letter? 
!
Current word: abacc
abacc not found

Challenge issued, player 1 has ["G", "H", "O"], all players: [[], ["G", "H", "O"]]

New word to pick
Player 1 pick a letter
Letter? 
a
Current word: ["a"], string: a

Player 0 pick a letter
Letter? 
b
Current word: ["a", "b"], string: ab

Player 1 pick a letter
Letter? 
a
Current word: ["a", "b", "a"], string: aba

Player 0 pick a letter
Letter? 
c
Current word: ["a", "b", "a", "c"], string: abac

Player 1 pick a letter
Letter? 
k
Current word: ["a", "b", "a", "c", "k"], string: aback

Player 0 pick a letter
Letter? 
!
Current word: aback

Challenge issued, player 1 has ["G", "H", "O", "S"], all players: [[], ["G", "H", "O", "S"]]

New word to pick
Player 1 pick a letter
Letter? 
a
Current word: ["a"], string: a

Player 0 pick a letter
Letter? 
b
Current word: ["a", "b"], string: ab

Player 1 pick a letter
Letter? 
a
Current word: ["a", "b", "a"], string: aba

Player 0 pick a letter
Letter? 
c
Current word: ["a", "b", "a", "c"], string: abac

Player 1 pick a letter
Letter? 
k
Current word: ["a", "b", "a", "c", "k"], string: aback

Player 0 pick a letter
Letter? 
!
Current word: aback

Challenge issued, player 1 has ["G", "H", "O", "S", "T"], all players: [[], ["G", "H", "O", "S", "T"]]

Player 1 loses, game over