Imagine evolution like this, a line 1,000,000 mm long, at the start it is 1,000,000:0 yellow:magenta pigment, the 2nd mm is 999,999:1 yellow:magenta, 3rd mm is 999,998:2 yellow:magenta and so on for the length of the line.
Now, what you'll end up with is a line with one end yellow, and one end magenta, but the changes are still small, you wouldn't be able to identify the single point on the line where it changes from yellow to magenta, because there isn't one, it's a combination of gradual changes.
Now, what you'll end up with is a line with one end yellow, and one end magenta, but the changes are still small, you wouldn't be able to identify the single point on the line where it changes from yellow to magenta, because there isn't one, it's a combination of gradual changes.