I can't follow what you are saying and trying to show. You might be able to do this in pure text and keep the characters where you want them better, if you put your text-attempted diagram between PRE tags.
Those would be like this:
Left arrow, p r e, right arrow
Your Diagram Using Pure Text
left arrow, backslash, p r e, right arrow
Look through the Show Source or Show Code hyperlink in this message and you should be able to see how the tags are arranged:
Item Name 8spaces
Item Name 16spaces
Item Name 24spaces