WHAT IS FANCY?

I am to write three lines, and you
Three others that will rhyme.
There—now I've done my task.

Three stupid lines as e'er I knew.
When you've the pen next time,
Some Question of me ask.

Then tell me, brother, and pray mind,
Brother, you tell me true:
What sort of thing is fancy?

By all that I can ever find,
'Tis something that is very new,
And what no dunces can see.

That is not half the way to tell
What fancy is about;
So pray now tell me more.

Sister, I think 'twere quite as well
That you should find it out;
So think the matter o'er.

It's what comes in our heads when we
Play at "Let's make believe,"
And when we play at "Guessing."

And I have heard it said to be
A talent often makes us grieve,
And sometimes proves a blessing.