What shape is the overlap when you slide one of these shapes half way across another? Can you picture it in your head? Use the interactivity to check your visualisation.

Take it in turns to place a domino on the grid. One to be placed horizontally and the other vertically. Can you make it impossible for your opponent to play?

Move just three of the circles so that the triangle faces in the opposite direction.

A shape and space game for 2,3 or 4 players. Be the last person to be able to place a pentomino piece on the playing board. Play with card, or on the computer.

If you can post the triangle with either the blue or yellow colour face up, how many ways can it be posted altogether?

How many balls of modelling clay and how many straws does it take to make these skeleton shapes?

A game for 1 or 2 people. Use the interactive version, or play with friends. Try to round up as many counters as possible.

What shape is made when you fold using this crease pattern? Can you make a ring design?

Hover your mouse over the counters to see which ones will be removed. Click to remove them. The winner is the last one to remove a counter. How you can make sure you win?

What does the overlap of these two shapes look like? Try picturing it in your head and then use the interactivity to test your prediction.

A game for 1 person. Can you work out how the dice must be rolled from the start position to the finish? Play on line.

Imagine a wheel with different markings painted on it at regular intervals. Can you predict the colour of the 18th mark? The 100th mark?

Players take it in turns to choose a dot on the grid. The winner is the first to have four dots that can be joined to form a square.

Seeing Squares game for an adult and child. Can you come up with a way of always winning this game?

I found these clocks in the Arts Centre at the University of Warwick intriguing - do they really need four clocks and what times would be ambiguous with only two or three of them?

Can you cut a regular hexagon into two pieces to make a parallelogram? Try cutting it into three pieces to make a rhombus!

An extension of noughts and crosses in which the grid is enlarged and the length of the winning line can to altered to 3, 4 or 5.

A game for 2 players. Given a board of dots in a grid pattern, players take turns drawing a line by connecting 2 adjacent dots. Your goal is to complete more squares than your opponent.

Here are shadows of some 3D shapes. What shapes could have made them?

Cut four triangles from a square as shown in the picture. How many different shapes can you make by fitting the four triangles back together?

The image in this problem is part of a piece of equipment found in the playground of a school. How would you describe it to someone over the phone?

Each of the nets of nine solid shapes has been cut into two pieces. Can you see which pieces go together?

Imagine a 3 by 3 by 3 cube. If you and a friend drill holes in some of the small cubes in the ways described, how many will have holes drilled through them?

In how many ways can you fit two of these yellow triangles together? Can you predict the number of ways two blue triangles can be fitted together?

Can you work out what is wrong with the cogs on a UK 2 pound coin?

Can you arrange the shapes in a chain so that each one shares a face (or faces) that are the same shape as the one that follows it?

What happens when you turn these cogs? Investigate the differences between turning two cogs of different sizes and two cogs which are the same.

Imagine a 3 by 3 by 3 cube made of 9 small cubes. Each face of the large cube is painted a different colour. How many small cubes will have two painted faces? Where are they?

This article looks at levels of geometric thinking and the types of activities required to develop this thinking.

Investigate how the four L-shapes fit together to make an enlarged L-shape. You could explore this idea with other shapes too.

Can you fit the tangram pieces into the outlines of the convex shapes?

Can you see why 2 by 2 could be 5? Can you predict what 2 by 10 will be?

Which of these dice are right-handed and which are left-handed?

If you split the square into these two pieces, it is possible to fit the pieces together again to make a new shape. How many new shapes can you make?

Have a go at making a few of these shapes from paper in different sizes. What patterns can you create?

A hundred square has been printed on both sides of a piece of paper. What is on the back of 100? 58? 23? 19?

These points all mark the vertices (corners) of ten hidden squares. Can you find the 10 hidden squares?

A game for 2 people. Take turns joining two dots, until your opponent is unable to move.

Paint a stripe on a cardboard roll. Can you predict what will happen when it is rolled across a sheet of paper?

Can you work out what shape is made when this piece of paper is folded up using the crease pattern shown?

Can you fit the tangram pieces into the outlines of the chairs?

Why do you think that the red player chose that particular dot in this game of Seeing Squares?

Can you logically construct these silhouettes using the tangram pieces?

Can you fit the tangram pieces into the outlines of the camel and giraffe?

Read about the adventures of Granma T and her grandchildren in this series of stories, accompanied by interactive tangrams.

Can you fit the tangram pieces into the outlines of Wai Ping, Wu Ming and Chi Wing?

Can you fit the tangram pieces into the outline of the dragon?

Can you fit the tangram pieces into the outlines of the rabbits?