Experiment with breaking up lines by characters

For ex, "1.1 Test" would be turn into:

1.1 test$1.1 Test
.1 test$1.1 Test
1 test$1.1 Test
test$1.1 Test
est$1.1 Test
st$1.1 Test
t$1.1 Test

But memory consumption for this is high compare to breaking the line
by words.

To break up the entries in list.txt:
By words: ~21 mb
By characters: ~191 mb