In this weeks parsha we find the Shira (the song) that Bnei Yisroel sang at krias yam suf (the splitting of the sea). There is a controversy in determining which verse is the last verse in the Shira. The posuk of ‘Ki va sus Pharaoh’ (when Pharaoh’s horse came) seems to be recounting the narrative of the miracle and is not worded in the more allegorical format of Shira. Conversely, this posuk is included in the special format used for writing Shira in the Torah. Each Shira in Tanach is written ‘ariach al gabe lavena’ (like bricks upon white space) as shown below.

xxxxxxx    xxxxxxx

    xxxxxxx

xxxxxxx    xxxxxxx

    xxxxxxx 

The alignment of ‘Ki va sus Pharaoh’ in the same arrangement as the previous verses seems to indicate its inclusion in the Shira.

The Baali Tosfos says, it was written this way to allude to a special characteristic of this great miracle. The sea divided into twelve walled paths, one for each tribe. Similar to the white spaces in the writing of the Shira, windows in the watery walls allowed the tribes to communicate with each other.