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The amazing ambiguous cube


This is a hands-on illusion you can build yourself.

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  • Print this document – you should have 3 identical pages.

  • Faintly mark where A is, then cut around the outline of the shape.

  • Using sellotape, stick the 3 shapes together with point A in the centre. You will end up with 3 sides of an odd-shaped cube.

  • Ensure you can’t see daylight through the gaps

  • Now place this cube on the floor and view from 2 metres away and slightly above, or get a friend to turn the cube very slowly.

  • The cube should flip in and out, like the necker cube.

  • Try experimenting with distances, angles and shadows to see what strengthens or weakens the illusions.

  • What you see is your brains best guess of what’s there – and this cube demonstrates this principle.

This amazing hands-on illusion is used with kind permission of the science magician Richard Robinson


What’s happening in your brain?


The cube is designed so that from certain angles it appears to be 3-D and sticking out.


When you look at this half cube, your brain automatically tries to visualise it in 3-D. As soon as you or the cube moves, or a shadow falls on the cube, it is revealed as the fraud it really is!


This ambiguous cube shows us that everything we see is just a ‘best guess’ by our visual system. Your visual system has a hypothesis that the cube is in one orientation, then if more information appears – for example if you move - another hypothesis is favoured and the cube reveals its true shape.


We never see both orientations together because your visual system must decide which hypothesis to favour. It does this every moment of every day.


For more illusions click here