In order to get the fading green color, the wooden sticks must be dunked for some time into each of these jars successively. The difference between the contents of the different jars is that the color is mixed in various concentrations in each of these jars.
The last is almost only color, whereas the first jar has some water also.
The addition of an extra color led to an addition of an additional taping station. Now we tape our sticks twice.
And the green color on the Green light is also shining twice!