The piyut Vechol Maaminim for Rosh Hashanah follows a pattern - two lines for each letter of the Hebrew alphabet, each one describing God in some way. However, the two lines for the letter Kaf seem to be the same thing: (from Wikitext)
הַכֹּל יָכוֹל וְכוֹלְלָם יָחַד
וְכֹל מַאֲמִינִים שֶׁהוּא כֹּל יָכוֹל
Why does the paytan repeat himself this way? Was there nothing else for the letter כ? The second line does not seem to add anything over the first.