I have been drawing this same logarithmic chart since March 13 when I was Comparing Coronavirus to other world tragedies.
At the date of March 15, 2020, I projected a straight line on the logarithmic chart by simply doubling the existing data line because this is a living system in a new medium. In this case, it is we humans who are the medium.
Two days earlier my chart was still mostly concerned with historical diseases, historical wars, Ebola cases, and Ebola deaths.
Doing the projection seemed a bit arbitrary, but it was painfully accurate.
We must hope that the curve will flatten, but we may look back a month from now on May 15, 2020, and think how lucky we have been to still be alive.
Twenty million cases seem totally impossible at the moment, and it is well known that statistics lie, and the world is only flat on paper maps.