ضَرَبَ زَيْدٌ عَمْرًا
Zayd struck ʿAmr.
In a simple verb–subject–object clause, the agent occupies the core subject role and the direct object normally follows. Moving that object before the verb is a conspicuous change.
But sentences with several dependents can have flexible relative ordering among them. The book therefore distinguishes object-fronting from placing one dependent ahead of another; their rhetorical explanations need not be identical.