Created by UK vision company Lenstore, the drawing is an example of the saturation ... also affect how we perceive pictures. When the blue circle is implanted on a lighter shade of blue background ...

paint the whole circle light blue. Once dry, use a blue felt tip pen to draw wavy lines across the whole of your circle. Start from the centre and work all the way down, and then all the way up ...

paint the whole circle light blue. Once dry, use a blue felt tip pen to draw wavy lines across the whole of your circle. Start from the centre and work all the way down, and then all the way up ...