What is the object of the sentenceGrandma bought Whitney a puzzle with over 1000 pieces?

The object of the sentence "Grandma bought Whitney a puzzle with over 1000 pieces" is the noun phrase "a puzzle with over 1000 pieces." In this sentence, the verb "bought" is acting on the direct object "a puzzle with over 1000 pieces," which answers the question of what Grandma bought. The indirect object "Whitney" indicates to whom the puzzle was bought.