Using a for loop, ask the user for the name of three items (animals, colors, fruits, or whatever you'd like).
Loop through the user's list and with iteration, print both the item and all the letters in the item.
Enter an animal: lynx
Enter an animal: ocelot
Enter an animal: puma
lynx
l
y
n
x
ocelot
o
c
e
l
o
t
puma
p
u
m
a
Loop through the list.
Loop through the letters of each word.
Create a list of the characters that occur in the words. If a letter has already been added to the list, skip it.
Output
Enter an animal: lynx
Enter an animal: ocelot
Enter an animal: puma
Letters used:
['l', 'y', 'n', 'x', 'o', 'c', 'e', 't', 'p', 'u', 'm', 'a']