What is the morphological pattern of muqattal?

Imruʾ al-Qays: Address to Fāṭimah, Parting, and the Arrows of the Eyes (Verses 19–22)

• A Form I imperative on the pattern ifʿal
• A Form II passive participle on the pattern mufaʿʿal
• A Form IV active participle on the pattern mufʿil
• A noun of place on the pattern mafʿal