Be a 2D shape detective

Shapes are all around us. But how much do you know about them?

Be a shape detective and find out more about 2D shapes.

About squares and rectangles

A square has 4 corners and 4 straight sides. The sides of a square are all the same length.

A rectangle is similar to a square. It also has 4 corners and 4 straight sides. But the sides of a rectangle are not all the same length. A rectangle has 2 long sides and 2 short sides. The sides of a rectangle that are opposite each other are always the same length.


Teacher notes

Point out to students that rectangles can be of different dimensions – as the rectangles in the painting illustrate.

You could demonstrate folding or cutting a paper square in half to show how this makes two rectangles. 

You could also show students how, if you fold or cut a square diagonally you get two triangles... to lead into the next section of this resource!



Here is another painting made from shapes. What shapes can you see?

Interwoven Coloured Triangles

Interwoven Coloured Triangles

Pamela Muriel Ward (1908–1994)

National Trust, Llanerchaeron

The painting is made of lots of brightly coloured triangles (and bits of triangles). Can you see a yellow triangle? Can you see a green triangle?

Try drawing a triangle in the air with your finger.

  • How many sides does a triangle have?
  • How many corners does it have?

Not all triangles look the same. Some triangles have sides that are all the same length, others have sides that are different lengths.

Triangle questions...

  • Can you find a triangle that has sides the same length?
  • Can you find a triangle that has sides that are different lengths?


About triangles

Triangles have 3 corners and 3 sides.

Some triangles have sides that are equal in length. These are called equilateral triangles.

Some triangles have 2 sides of the same length and one side that is a different length. These are called isosceles triangles.

Triangles that have sides that are all different lengths are called scalene triangles.



Top tip! If a triangle has sides that are all the same length it will look exactly the same if you rotate or turn it once, but a triangle with sides that are different lengths won't.


Teacher notes

Although students don't need to learn the names of the different types of triangles, it is useful for them to understand that triangles are not all the same. You could ask them to point out the different types of triangles on the drawing.

Use a template of an equilateral triangle to demonstrate that when it is rotated 90 degrees it looks the same.


Did you know?

A triangle is the strongest of all the shapes. Objects and buildings that need to be strong, often have triangles in their structure.

  • Can you spot the triangles in these bridges?


Forth Bridges

Forth Bridges

Clive Anderson Watts (b.1943)

NHS Fife

  • Can you spot the triangles in the frame of this (extremely long) bicycle? (A bicycle made for five people would have to be very very strong!)


  • Look out for triangles in buildings and bicycles when you next go for walk...


Pentagons, hexagons and octagons

Can you see some shapes with lots of sides and lots of corners?


Can you work out what they are?

Here are some clues...

  • A pentagon has 5 sides and 5 corners – can you find a pentagon?
  • A hexagon has 6 sides and 6 corners – can you find a hexagon?
  • An octagon has 8 sides and 8 corners – can you find an octagon?


Did you know?

The black and white pattern on a football is made from pentagons and hexagons.

Look at this sculpture of a football.

Angled Ball

Angled Ball 2011

James Hopkins (b.1976)

B4557, Brent

  • What colour are the hexagons?
  • What colour are the pentagons

Top tip! Count the sides of the shapes to find out what they are.


The honeycombs where bees store their honey are made from lots of hexagon-shaped cells.

Western honey bee on a honeycomb

Western honey bee on a honeycomb


You might spot an octagon on your way home from school...!

Stop sign

Stop sign



Circles are all around us.

  • Try drawing a circle in the air with your finger.
  • Can you see any circles in this painting of a market stall?


Portobello Veg Stall

Portobello Veg Stall

Christopher Corr (b.1955)

The Nightingale Project

  • How are circles different from all the other shapes we have looked at so far?
  • How many corners does a circle have?
  • How many sides does it have?


Homage to the Circle II

Homage to the Circle II

Kajt Kapolka (b.1921)


About circles

All the shapes we have looked at so far have straight lines, but circles are made from a curved line and have no corners.

They also only have one side. All the other shapes we have looked at have 3 or more sides.



If you cut a circle in half, you get a very different shape called a semi-circle.

This sculpture was made by an artist called Barbara Hepworth. It is made of two semi-circles with circles inside the semi-circles. (Barbara Hepworth often added circles to her sculptures.)

  • Can you spot the semi-circles?


Two Forms (Divided Circle)

Two Forms (Divided Circle) 1969

Barbara Hepworth (1903–1975) and Morris Singer Art Foundry Ltd (founded 1927)

Deane Road, Bolton, Greater Manchester

  • How is a semi-circle different from a circle?
  • How many sides and corners does it have?
  • Is it made from curved or straight lines?


About semi-circles

A semi-circle is half a circle. It is different from a circle because it has 2 sides – a straight side and a curved side. It also has 2 corners, while a circle has no corners.

Circles and semi-circles

Circles and semi-circles


2D shapes and symmetry

If you draw a line down the centre of a circle, the two halves are exactly the same.

Shapes that have two identical halves are symmetrical shapes.

Have a look at these 2D shapes. Imagine drawing a line down the centre of them from the top to the bottom.

  • Would each half look exactly the same?

2D shapes

2D shapes

All of these shapes have a vertical line of symmetry. (A vertical line is a straight line that goes up and down.)

Now imagine drawing a line through the middle of each shape from side to side. (A line that goes from side to side is called a horizontal line.)

  • Would each half look exactly the same?
  • Are there any shapes that would have different shaped halves?


Teacher notes

It may be helpful to fold paper shape templates in half to illustrate the vertical and horizontal lines of symmetry.

For more advanced students you could also introduce the idea of multiple lines of symmetry.

  • A square has four lines of symmetry.
  • An equilateral triangle has three lines of symmetry.
  • A circle has infinite lines of symmetry.

Activity: I spy 2D shapes challenge

As a class, look through the artworks in the slideshow below and ask your students to find 2D shapes.

You could approach the challenge as an 'I spy' game.

  • Ask individual students in the class to choose a shape they can see and tell the class the letter that the shape name starts with ('I spy with my little eye a shape beginning with [letter]')
  • The rest of the class should then try and spot the shape in the picture and describe what its properties are.


Art & design activity suggestions

Before the lesson

Prepare shape templates for students to draw around (squares, rectangles, circles, triangles, etc.).

Shape templates

Shape templates

You could either make card templates or collect objects such as bottle tops or jar lids, tin cans, dominoes, etc. – anything that has a circular, square or rectangular face. (Objects with triangular, hexagonal, octagonal and pentagonal faces may be harder to find so you may need to make these templates!)

Make an abstract picture or pattern from 2D shapes

In this resource, we have looked at lots of paintings, prints and drawings. Many of these are abstract artworks made from geometric shapes.

Task your students with making an abstract picture or pattern using the shape templates.

  • They could overlap the shapes (as artist Pamela Ward has done with her Interwoven Triangles) and then paint or colour in the new shapes that have been made by the overlaps.

(For more detailed activity instructions, see the Art UK activity: Make a 2D artwork from abstract shapes.)

Interwoven Coloured Triangles

Interwoven Coloured Triangles

Pamela Muriel Ward (1908–1994)

National Trust, Llanerchaeron


  • They could arrange and repeat shapes across the page, combining one or two shapes to make a pattern. Encourage them to think about the order or sequence of their arrangement.

Equilateral No. 15

Equilateral No. 15 1997

Simon Willis (1933–2003)

St George's Hospital


  • Or they could explore shapes that fit together or tesselate, to form a pattern. (Find out more about tesselation in this BBC Bitesize guide.)


Urban 2006

Tony Morin (active 2000–2009)

Bethlem Museum of the Mind


Be inspired by more abstract pictures and patterns made using shapes, on Art UK:

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