费尽心机

Explanation: Effort: tricks. Rack their brains to try approach. 　　Usage: Verb-object type; as predicate, object; thoughtful planning for human 　　Source: Song Dai, "On Poetry Review Shiping collection": "Sometimes not staggering sentence, scheming impossible to do." 　　Examples: He ~, and finally came up with a good idea. Thesaurus:  Tricks, body eat, eat thinking