We will focus on a kaleidoscope of this type. Three front-surface mirrors are set together to form
an equilateral triangle, as shown in the figure below.
Standard, household mirrors have a protective layer, such as glass, covering the reflective surface.
First- or front-surface mirrors do not have a heavy protective surface. Additionally, the elimination
of a protective surface simplifies the optics!
Light rays are assumed to bounce off the mirrors like a ball bounces off a hard surface.
Formally stated, the angle of incidence equals the angle of
reflection.1 Images are located where
the outgoing light rays appear to intersect.2
Go to first reflection images.
1 A somewhat mathematical discussion of where this law comes
from is at Reflection Angle Rule.
2 If you are not familiar with locating a flat mirror
virtual image, you might consider looking over
Locating Flat Mirror Virtual Images, which
is an animated gif. Those using a screen reader or the Google translator are
directed to the translatable presentation of
Locating Flat Mirror Virtual Images.