Many groups of plants have developed iridescence as an adaptation to use more light in dark environments such as the lower levels of tropical forests. The leaves of Southeast Asia's Begonia pavonina , or peacock begonia, appear iridescent azure to human observers due to each leaf's thinly layered photosynthetic structures called iridoplasts that absorb and bend light much like a film of oil over water. Iridescences based on multiple layers of cells are also found in the lycophyte Selaginella and several species of ferns.  
Another way to use ou big sheet of paper is to make an accounting book . I'm no accountant, but let's imagine that we would have a page for "expenditures", "purchases"... That's nice because now we can query things like "give me the total revenue" very quickly (just read the "purchases" page). We can also ask for more involved things like "give me the top ten products sold" and still have acceptable performance. But now consider how painful it would be to find the expenditures for a particular user. You would have to go through the whole list of everyone's expenditures and filter the ones of that particular user, then sum them. Which basically amounts to "read the whole book" again. That would be a column-based database (OLAP).