What do the endings “manzil” and “Ḥawmal” illustrate?

Qalb, Tashrīʿ and Luzūm Mā Lā Yalzam: Completing the Verbal Ornaments

• The entire verse is a palindrome
• They have different central rhyme consonants
• All letters before lām are identical
• Both share the lām rawī though preceding letters differ