You may also like


Imagine an infinitely large sheet of square dotty paper on which you can draw triangles of any size you wish (providing each vertex is on a dot). What areas is it/is it not possible to draw?

All in the Mind

Imagine you are suspending a cube from one vertex and allowing it to hang freely. What shape does the surface of the water make around the cube?

Reflecting Squarely

In how many ways can you fit all three pieces together to make shapes with line symmetry?

Concrete Wheel

Age 11 to 14 Challenge Level:

Imagine that you are sitting in a room at ground level, facing a floor-to-ceiling window which is 20 feet by 20 feet.

A huge concrete wheel, 100 miles in diameter, is rolling down the street and is about to pass right in front of the window, from left to right.

image of wheel and window
The centre of the wheel is moving to the right at 100 miles per hour.

What does the view look like, from inside the room, as the wheel passes by?

This problem appears in "Mathematical Thinking and Problem Solving", edited by Alan Schoenfeld and published by LEA press.