There’s only four pieces, but this puzzle is Totally Tricky!
You will need
- A printout of the T-puzzle template
What to do
- Cut out the four pieces.
- Rearrange them so they make a capital T shape.
- Don’t give up!
- Try drawing a T shape. Make it as close to the answer as you can imagine.
- Think about all the corners a T shape has. You’re going to need lots of right angles.
- Do any of your pieces have special angles?
- The funny 5-sided shape is very important. You don’t have to fill the hole in it.
- One of the pieces has to go ‘diagonally’.
This conundrum has been puzzling people for over a century. A scientific study found that most university students could not solve the puzzle in 15 minutes, and they needed hints to finish it.
There are a few things that people often get wrong with this puzzle. It is very tempting to fill the gap in the 5-sided piece. The gap is a right angle and each of the other pieces will fit in there. But the gap is a red herring. You have to leave it empty to solve the puzzle.
People also want to put all the pieces running left to right, or up and down. A T shape is made of horizontal and vertical lines, but in order to solve the puzzle the 5-sided piece needs to be on a 45° angle.
The 5-sided shape is the key piece. When a group of students were given this puzzle with the 5-sided shape in the right place they all solved the puzzle in minutes. Without this hint, the puzzle usually takes a lot longer. Famous mathematical journalist Martin Gardner once said, “I know of no polygon-dissection puzzle with as few pieces that is so intractable.”
View the solution
If you’re after more maths activities for kids, subscribe to Double Helix magazine!