Have you ever taken the time to measure a pencil?
I'm guessing that you haven't. And good, because measuring a pencil is a massive waste of time: the more you use a pencil, the shorter it gets!
It's like some kind of terrible magic trick.

However, if you were to measure a pencil before you started to use it, you would find that it is exactly 20cm long. That's 7.87401575 inches: exactly the same length as a smear I once saw!

Perhaps you can imagine my surprise when I waltzed one day into my local stationery supplier, began measuring the pencils on display, and discovered a pencil measuring a whopping 30cm long: much longer than even the longest smear in the world!

I'll save you the imagination time - such was my surprise, that I soiled myself rather violently!
By the time I had recovered, the pencil had been purchased.

Yes, the day I discovered the longest item of stationery was a day I shall never forget!