Imagine you are a chief of a tribe. You feel yourself very important. And to fulfil your obligations to your god you manage to convince your people to build a huge mount. A pyramid you may say. You want to surpass all earlier attempts of predecessors to create one so this pyramid must be at least 290 x 255 meters at the base, and the upper level –your plan is to built a four level pyramid -will be about 28 meters.

Your people are deep believers and follow you in your vision, but how do you do that undertaking? How much labour is needed? How long will it last? Will it be finished before you die? Even the healthiest of your tribe didn’t live longer than 60 years. So you start calculating, and to keep the things simple, you limit the idea to ‘a simple sand pyramid’. Sand can be transported using baskets. Each basket may contain roughly 5 litres of sand and a worker will do about 10 baskets per minute you think.

After some headache of calculating you are sure that the volume of your future pyramid is about 1,7 billion litres of sand. How to accumulate such an enormous amount of sand?

You are optimistic about your chances for life, but dare not to reckon with more than 20 years for you to finish your pyramid. Of course you would like to have at least a few you’re the enjoy the finish pyramid. So that’s about 10 million minutes to transport the 1,7 billion litres of sand, so about 160 litres of sand per minute, 24 hours a day, day-in-day-out.

Because of the size of your pyramid, you already know that the average distance from t

he pyramid to the sand quarry will be about 2 kilometres and if you place a dock-hand every one meter, you need a workforce of more than 6000 men. And of course you allow them to have some rest and time for others things to do, so you calculate with a 3-shift workforce. You are happy that you only need about 19000 men to carry the sand in long rows in parallel.