and down up and down
and down up and down .
a n d WORD_BOUNDARY d o̞ w n WORD_BOUNDARY u p WORD_BOUNDARY a n d WORD_BOUNDARY d o̞ w n WORD_BOUNDARY
a n d WORD_BOUNDARY d o w n WORD_BOUNDARY u p WORD_BOUNDARY a n d WORD_BOUNDARY d o w n WORD_BOUNDARY . WORD_BOUNDARY