The man tells you, "To enter the door of infinite precision, you must complete all of these tasks perfectly:
- Hold in front of me a baby that is exactly two days old.
- Bring me a metal object that weighs exactly one kilogram.*
- Bring me a stone object that weighs exactly one pound.*
- Bring me a glass containing something other than water that is exactly the same density as water.
- Write all the digits of pi."
"I'm sorry", you say, "but that is impossible. I can complete four, but there is one I cannot do."
Which task can't you accomplish, and why?
(The explanation should state how you can do the other four tasks, as well).
Keep in mind that this puzzle was spoken, not written down. This may help with one of the tasks.
*If you want to get technical (and I know some of you do), consider these objects with a mass of one kilogram and one pound.