How can I write a loop using letters instead of numbers so it looks like this:
2 sets used 'a-z' and 'A-Z'
aaaaa
aaaaA
aaaAa
aaAaa
and so on:
aaaAA
then on to b:
bbbbb
bbbbA

I can do it with numbers, something like this:

for i in range(10):
for j in range(10):
for k in range(10):
print i,j,k

This is not true, or you did not show us that. Your code does not produce the desired output, and it is not, that it has numbers instead of characters.

I think the problem:

writing a loop with letters not numbers

is solved.

Please open a new topic with something similar:
help with simple discrete math homework.

def Separate (strng):
uppers = []
lowers = []
for letter in strng:
if letter.isupper():
uppers.append(letter)
else:
lowers.append(letter)
print "Lowers:",lowers
print "Uppers:",uppers

This is not true, or you did not show us that. Your code does not produce the desired output, and it is not, that it has numbers instead of characters.

I think the problem:

is solved.

Please open a new topic with something similar:
help with simple discrete math homework.

I will gladly help.

I put a loop up of numbers to show that I can run a loop with a given amount of chars. I can add 2 more values to it if a list of 5 is what I'm after. Running the numbers loop will produce:
0 0 0
0 0 1
0 0 2
and so on. After the suggested use of chr() I was able to write the loop to use letters instead of numbers but my original question was how to do this with uppers as well as lowers:

How can I write a loop using letters instead of numbers so it looks like this:
2 sets used 'a-z' and 'A-Z':

At your suggestion, I will mark this as solved and start a new post.

I want to implement undo logic which deletes the last drawn shape. To test this logic i had cleared shapes list and redrawn all shapes but still last ...