Laser ray captured between two glass surfaces

 Photo 1. The laser ray is captured between two glass surfaces.  
 Picture 2.  The incident, reflected, and refracted rays are sketched.  Notice that the two refracted rays at the left are parallel (the same angle of refraction!)
Picture 3.  White A at the right side indicated an incident angle; the blue A shows a reflected one. All angles A are equal.  B in lower right corner is an angle of refraction, other B-angles are both incident and reflection angles. All angles B are equal.