XMAS tree for 3mm (fading) leds

In contrast to most of the Thingiverse christmas trees, this one is for 3mm leds.
Red leds have a voltage drop of 2 volts. If we take three of them in series with a 9 volt block cell and 5mA led current, we can use a 560 Ohm resistor (see illustration).
Blue and green leds have the same resistor but only two leds in series.

Slow fade leds give an interesting tough if we use them as well.
And the price for 50 of these leds is incredibly low as one of the illustrations shows.
No microproces