The US follows Europe's path and flattens its curve of cases. China & South Korea have already a flat curve.

Cumulative numbers of confirmed cases in selected countries after the 100th case, last updated with the numbers from yesterday, smoothed with a seven day rolling average. These numbers don't tell us anything about the number of infected people, just about the number of people who got tested positive.

The helper slopes don't mark corridors. For example, Europe has a doubling rate of less than three days now – the "...every 3rd day" slope is steeper than the Europe line. 

The 100th cases of all countries are aligned and therefore approximated. The chart shows only confirmed COVID-19 cases in counties with more than 1000 of them. The source didn't report values for China before their 500th case, so the numbers of days passed after their 100th case is estimated.
Chart: Lisa Charlotte Rost, Datawrapper.Source: Johns Hopkins CSSE