Try sitting straight on a chair, with your back and lower legs vertical, and your thighs horizontal. You will discoed that if you neither move your feet nor bend your torso forward, it is impossible to stand up.

Feel free to try it. You will be unable to stand until you either move your feet back, or your chest forward.

Hello my dear Sherlocks, Einsteins, and other puzzle solvers. You’re probably all cooped up and sick of your family at this point, and need something to keep morale up.

Well, I got just the thing for you.

As always, the solution to the riddle is in the comments.

The mathematics of infinity can be startlingly beautiful. It can allso be just plain startling.

Consider the natural numbers – 1, 2, 3, 4, etc. They are infinite; any number you can conceive of can be increased. Now consider the even natural numbers – 2, 4, 6, 8, etc. These also obviously extend to infinity.

So if you compare the set of all natural numbers with the set of all even natural numbers, which is larger?

Hello my Little Einsteins, I hope you have your thinking caps on. Today’s puzzle is all about windows, which really doesn’t make a difference for a genius like you!

And as always…answers are in the comments.

Imagine that you have a square window, five feet high, set in an opaque wall. That window lets in a certain amount of the available light outside. Simple.

It is possible to modify the window to precisely halve the amount of light that it lets in without changing the type of glass, placing a curtain, filter, or any other sort of obstruction over the window or between the window and the viewer — while still keeping the window square, and five feet high.

Hello everybody, I hope you have your thinking caps on! I’m back for another Solve it Sunday post, and this week is a tricky one.

As always, answer is in the comments, and you think you have the right answer, make a comment of your own.

During the 19th century, a European colonel in Ethiopia recorded a report of an encounter with local tribesmen, from whom he was purchasing cattle.

He wanted seven beasts, at a cost of 22 birr each. Not being numerate, the herder called a local priest to verify the total price.

When he arrived, the priest dug two parallel columns of holes. The right-hand column represented the purchase price, so in the first hole he placed 22 stones, and then halved the number of stones for each subsequent hole, rounding down. This gave him 22, 11, 5, 2 and 1 stone.

The left-hand column then represented the cattle, and in the first hole he placed seven small stones. He then doubled the number of stones for each subsequent hole in the column, so that the holes contained 7, 14, 28, and 112 stones.

Declaring even values to be evil, the priest then went down to the right-hand column and whenever he encountered an even number of stones – the 22 and 2 holes, in this instance – he removed the stones from that hole and its neighbor in the left-hand column – 14, 28, and 112 respectively – into one pile, which he counted out one by one.

They came to 154 birr, which was indeed 22×7.

Indeed, this technique of multiplication will always work for whole numbers, but why?

Now for a little practical experiment – one that you, dear reader, are able to take part in without any undue effort. Exhale slowly and steadily into the palm of your hand. Make a mental note of how it feels. Now purse your lips, and blow vigorously onto your palm. You may use the other hand if you wish.

You will observe that when breathing slowly, the air feels warm, but while blowing firmly, the air feels cool.

Your breath has not changed temperature. Neither has your hand. So why is there a difference?

Good luck everyone, and just remember, simple is sometimes the answer.