Exponential growth happens when an organism has no limit of resources and no predators. We all know the graph; pokey, pokey, blip then zoom. Growth on the vertical and time on the horizontal.
When humans cluster together in our usual fashion we allow the graph of the growth of SARS-CoV-2 to form a steep incline, picture an upside down ice cream cone. With the effort to flatten the curve by social distancing, sheltering in place, and quarantine of infected persons we hope to spread the area of the same tall ice cream cone into a short, squat muffin top that takes a bit longer time to manifest in totality. With the ice cream cone it is predicted in the US that 75% of our population will have contracted COVID-19 by July 1, 2020. With a muffin top that number may only be 25 to 50% by the same date.
The muffin top is our flattened curve.
I've taken some liberties here with using just words for what is best shown in an illustration found nearly everywhere on the web.
Here is one example.
and here is my favorite example,#CATTENINGTHECURVE.
The dates information is from a wonderfully illustrated and animated article (no pay wall) in the New York Times today.