Category Archives: Practical

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Below you can read the steps of a magic trick, as well as a video of its live performance. Your goal is to figure out how the trick is done, then perform it for your friends and challenge them to figure out the trick themselves.

  1. Take out from your pocket a deck of cards, which is visibly shuffled.
  2. Ask your first assistant to cut the deck, then take the top card from the bottom pile of cards and memorize it.
  3. Ask your second assistant to take the next card from the bottom pile and memorize it.
  4. Ask your first assistant to return his card back on the top of the bottom pile, then ask your second assistant to do the same.
  5. Place the two piles of cards on top of each other and cut the deck multiple times.
  6. Split the deck into two piles of cards, dealing consecutively one card on the left, then one card on the right, and so on, until you run out of cards.
  7. Take one of the two piles of cards, look at it, and guess correctly what cards were chosen by your assistants.

How does the magic trick work? Below you can see a live performance of the magic trick from Penn and Teller’s show Fool Us.

The secret of the trick is to memorize the group of cards which are located in even positions and the group of cards which are located in odd positions in the original deck. An easy way for doing this is to split the cards into two groups, such that the cards in the first group are only spades and diamonds, and the cards in the second group are only clubs and hearts.

When the two assistants pick their cards and then return them back into the deck, the order of the cards is reversed. When you split the original deck into two piles (even after cutting it several times), each of the piles will contain a card which should not be there. For example, the group of spaes and diamonds will contain one clubs card, and the group of clubs and hearts will contain one diamonds card. These two cards are the ones which were picked by the assistants.

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This is a puzzle which is best played with friends and real dice on a table. The rules require one of the players to throw 5 dice at once, and then answer correctly “how many petals there are around the rose”. The procedure gets repeated until everyone has discovered the secret rules of the puzzle or has given up.

How many throws do you need in order to figure out this classic puzzle?

There are 6 petals around the rose.

The roses are the middle dots on the dice, and the petals are the dots around them. Just count the number of all petals appearing on the five dice and you will get the answer. 1 -> 0, 2 -> 0, 3 -> 2, 4 -> 0, 5 - > 4, 6 -> 0.

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First, print and cut the pieces below. Then, arrange them so that they form a triangle and then rearrange them so that they form a square.

The solution is shown below.

What is fascinating about these dissections is that one can transform into the other by keeping the pieces attached to each other in a chain and simply rotating them around the hinge points.

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Prepare a piece of paper with dimensions 2×4, then fold it four times to form 8 squares. Write on the squares in the top row the numbers 1, 8, 7, 4, and write on the squares in the bottom row the numbers 2, 3, 6, 5.

Now your task is to fold the piece of paper several times, so that the squares end up on top of each other, with the numbers appearing in ascending order top to bottom, and 1 face up.

Once you do this, try again with numbers 1, 8, 2, 7 on the top row, and 4, 5, 3, 6 on the bottom row.

Coming soon.