A sequence is an ordered list which contains elements.
The number of ordered elements (possibly infinite) is called the length of the sequence.
Order matters,and exactly the same elements can appear multiple times at different positions in the sequence.
They represent a part of a picture.
They are stacked on top of each other, and depending on the order, determine the appearance of the final picture.
-black.white and gold paint
-40 different segments on one wall