Multicolor led with 2 pins

Hi,

I break a multicolor night light and find that it has only one radial
led but it is multicolor (red, blue,) and of 2 pins. How to do that?
Do anyone see similar design or LED before? The night light turns its
color gradually from red to green and to blue and then recycle. Is it
used different voltages to control the colors?

Thanks!

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