Similar-looking characters are commonly substituted for one another : for instance , o , O , and 0 can all be used interchangeably , sometimes for subtly different effect or , in some cases , one type of character may look better in a certain font and therefore be preferred over another .
In general , similar-looking characters are commonly substituted for one another : for instance , o , O , and 0 can all be used interchangeably , sometimes for subtly different effect .