Reverse a string without using reversed() or [::-1]?

Question

I came across a strange Codecademy exercise that required a function that would take a string as input and return it in reverse order. The only problem was you could not use

Answer 1

The way I can think of without using any built-in functions:

a = 'word'
count = 0
for letter in a:
    count += 1

b = ''
for letter in a:
    b += a[count-1]
    count -= 1

And if you print b:

print b
drow