Google-sheets – Possible to add a third color to a ‘bar’ sparkline

I have three columns of data that I want to represent with sparklines as a stacked bar chart.

For instance, a row like

12  5   1

with this formula

=SPARKLINE(C2:E2,{"charttype","bar"})

shows an image like this:

As you can see, the first and third colors are the same. I would like to specify all three colors, so that the first and third colors are different.

Google's SPARKLINE Help docs indicate bar charts set two colors by default; these can be user specified as color1 and color2. They do not provide any instructions for specifying additional colors.

I have tried specifying color1, color2, AND color3, and I have tried specifying lastcolor; neither option alters the third color. I also tried setting just color, then specifying color1 and color2 as a default, to see if Sheets would default to the setting for color for the third color. That did not work either.

Is there a way to set the 3rd color to be different from the first color?