I have a fruit tree in my backyard that makes fruit to order. I go out to the tree. The tree says, “Yes, Fred?” I request a particular piece of fruit. The tree says, “Okay, it will be a few minutes.” I take a seat in a chair next to the tree. There’s a small table next to the tree with a few magazines and a tip jar.
After a moment the tree produces the requested fruit, or something very near it. Once I asked for a Stayman apple and I got a Fuji instead.
I remove the fruit from the branch and eat the fruit. Sometimes it’s a grape. Sometimes a watermelon. Today I had a papaya.
The rest of the time the tree has no fruit on any of its branches. I asked once why it won’t make unordered fruit. The tree said, “It’s a lot of work to make fruit. If you don’t want any, I’m not gonna waste my time.”