والشمس كالمرآة في كف الأشل
And the sun is like a mirror in the palm of a person with a paralysed hand.
The comparison term is not simply a mirror but a mirror held in an unsteady or impaired hand. That condition affects the imagined movement and play of light; omitting it would remove an important aspect of the likeness. The sun is not expressly qualified in the same way.
This illustrates a mixed qualification: one term is restricted by a relevant circumstance and the other is not. The classification records the actual function of each term, not a requirement that they have identical grammatical structure.