In the first phase of trance an altered state of consciousness would come about. People would experience geometric shapes commonly known as entoptic phenomena. These would include zigzags, chevrons, dots, flecks, grids, vortices and U-shapes.
During the second phase of trance people try to make sense of the entoptic phenomena. They would elaborate the shape they had ‘seen’ until they had created something that looked familiar to them.
In the third phase a radical transformation occurs in mental imagery. Subjects have found that they experience sliding down a rotating tunnel, entering caves or holes in the ground. People in the third phase begin to lose their grip on reality and hallucinate monsters and animals of strong emotional content. In this phase heightened sensory awareness gives one the feeling that they have undergone a physical transformation.