ka·lei·do·scope | \kə-ˈlī-də-ˌskōp \
“observation of beautiful forms”
The word kaleidoscope is derived from the Ancient Greek καλός (kalos), “beautiful, beauty”, εἶδος (eidos), “that which is seen: form, shape” and σκοπέω (skopeō), “to look to, to examine”, hence “observation of beautiful forms.”
A kaleidoscope is made of two or more mirrors or reflective surfaces positioned at an angle to each other, usually forming a V-shape or a triangle. The case is the body surrounding the mirror assembly. A collection of objects is positioned at one end of the mirrors, and there’s an eyehole at the other end.
What you see when you look through that eyehole will never be exactly the same twice. While the container holding the objects is often as large as the kaleidoscope tube, only the portion of the objects that fall within the space of the triangle within the object holder is reflected.