Buying a ruler

I needed a ruler

And went to the shop to get one

But the rulers were all straight

And I wanted to draw

A curving line 

.

Now, why are they so?

Oh! They go by the rule

That is why.

So then

If you can’t get a ruler

That will help you

To draw a bent line

Or a curved one

Then what can you do?

You will have to draw it,

He said,

And that is why I draw.

(And I very well know

That there are rulers

That will bend a law or two.)