The Purple Orb

So I got this gift.

A Purple Orb that can guess what you are thinking of by asking 20 simple yes/no questions.

Uncanny.........
Out of about 20 tries, it has successfully deduced the item about 18 times.

Golf Ball
Pocket Knife
Electric Guitar
Guitar Pick
Mechanical Pencil
Coffee Mug
Bridge
Trash Can
Piano
Baseball
Giraffe


and more I forget the rest ...

It got Clock for Watch and Plant for Tree

I am Fascinated by this thing. How can it figure out specific items from such general and vague questions it asks.