Typing "O" and meaning the letter... not the origin
I am working on some cryptography worksheets. I need to be able to type letters in as the 'key' (say for a substitution cipher). I'm using the spreadsheet as a place to have an easily editable list of letters. Unfortunately every time I type the letter O (in capitals) it assumes I mean the origin point (0,0) - and it does something weird to anything else I've recently typed into the spreadsheet (seems to undo any recent changes). If I type "O" with the quotes it seems to behave better, but it's really hard to remember to do this if I am just trying out a different key, and quickly type a O where I think it should be. I have never defined the origin point in this worksheet, but it seems to be built in that O means the origin... is there any way to stop this behaviour? Is it just me? Any other suggested workarounds?
Thanks in advance,