It is a toy which contains is made up of multiple plane mirrors.
Due to multiple mirrors, There are multiple reflections of light in a kaleidoscope which forms beautiful pattern.
How to make a Kaleidoscope?
We follow these steps
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   Take 3 rectangular mirrors
   
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   Join them by its length, so that mirrors are facing inwards
   
   
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   Put them in a circular tube made of cardboard. Make sure length of tube is a little longer than the mirrors
   
   
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   Close one end of the tube by cardboard
   
   
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   Make a hole in the center - so that we can see through it
   
   
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   In the other side, place pieces of bangles.
   
   
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   And cover it with a glass plate
   
   
 
The Kaleidoscope is ready
When we peep through hole, and rotate the cardboard tube slightly, we will be able to see beautiful different patterns.