Your record
How to play
- 1
Start on any dot and slide your finger along a line to the next dot. Tapping dot after dot works too.
- 2
Use every line exactly once and never jump. The whole figure becomes one unbroken line. Got stuck? Undo or start over.
- 3
Some figures can’t be done at all. If you think so, tap Can’t be done. In Today’s 5 a wrong call loses that figure, so be sure.
Questions
Is there a trick to tell which ones can’t be done?
Yes, and it is a famous one. Count the lines at each dot. If more than two dots have an odd number of lines, the figure can’t be drawn in one line. If exactly two do, start at one of them and you will end at the other. If none do, start anywhere. Leonhard Euler found this in 1736 with the bridges of Königsberg.
What do the age bands mean?
Levels come in three bands of 200: ages 6 to 8 have small figures with a few lines, ages 9 to 12 have bigger ones with crossings, and 13 and up has big figures that trap a careless start. Anyone can play any band.
Is it the same for everyone?
Yes. Everyone gets the same five figures each day, from a small one to two big ones. Your score is how many you got right and how long it took. Levels are the same for everyone too.
Why is the line rainbow coloured?
The colour runs from red to violet in the order you drew, so you can see where you started and how the line travelled.
Is it good for kids?
It is a gentle way to practise planning ahead and spotting patterns, and the trick behind it is real maths (graph theory). Start kids on the Ages 6–8 levels and let them find the trick themselves.