This Unicode document contains the following paragraph :
"Vowel Letters. Vowel letters are encoded atomically in Unicode, even if they can be analyzed visually as consisting of multiple parts. Table 9-1 shows the letters that can be analyzed, the single code point that should be used to represent them in text, and the sequence of code points resulting from analysis that should not be used."
What do they mean by can be analyzed visually and sequence of code points resulting from analysis that should no be used ?