<.A.BC> -> Incorrect because of odd byte length
<.A.B><.C> -> Incorrect contiguous SO/SI
<> -> Incorrect contiguous SO/SI (null DBCS symbol)
<.A<.B>.C> -> Incorrectly nested SO/SI
<.A.B.C -> Incorrect because SO/SI not paired
<.A. .B> -> Incorrect because contains blank
'. A<.B><.C> -> Incorrect symbol