m[^         # With the $, match the whole line
   (\S+)    # The first field contains no spaces
   \s+      # and is separated from the next by at least 1
   \b(.*)\b # 2nd field starts/stops on a word boundary
            # it can contain anything, 
   \s{2,}   # but only single concecutive spaces.
   \b(.*)\b # 3rd field is similarly defined
   \s{2,}   # Again, 2 or more spaces defined the end of field
   (\S)     # 4th Single non-space char
   \s+      # 1 or more spaces
   (\S)     # 5th Single char.
$]x