Massive green rotating disc-shaped lights over Portland.Looking eastward over the lake/reservoir at Progress Ridge near the Beaverton/Tigard border, two male adult friends and I observed in the distance three radio towers situated in the West Hills that separate downtown Portland from its Western suburbs. It is important to note that the cloud cover was low, but not low enough to obscure any portion of the radio towers in the distance. I'll take this opportunity to say I don't believe what we saw was fireworks exploding within the clouds.In the clouds that appeared to be over the West hills and said radio towers we observed first a massive green light that rotated counter-clockwise. It was orientated as though it was parallel to the ground, and made perhaps only a 90 degree rotation until it disappeared but was replaced (within one second or so) by the exact same shape, only this time in an incredibly quick burst of yellow, then orange, then red colors acting in the same manner.Some 20 seconds later, the exact same reen shape and light occurred again, rotating in the same direction and for roughly the same short amount of time, perhaps a few tenths of a second shorter. Next, only the yellow-colored shape appeared, not the red nor the orange.The object certainly appeared to be concealed precisely within the clouds that were illuminated by the city lights of downtown Portland, but they were absolutely distinct from those city lights.It reminded me of the handheld game "Simon Says" the way the colors changed from one to another, and the nature of the colors was reminiscent of the the taillight of a car, as if there was a membrane containing an inner light-producing object.There were also a larger number of aircrafts in that apparent area of the sky just before the lights occurred. Perhaps this could be explained by the vicinity of PDX airport, but the aircraft seemed to remain in the affected area for a far longer time than one would expect of any aircraft approaching the airport. They also seemed to be physically closer to one another than is seemingly typical for civilian aircrafts. I am no expert in aviation by any means, but it seemed as if they were flying in formation, sort of like you'd see whenever those F16 (or various fighter jets) fly overhead every so often (they didn't sound like fighter jets, I might add.) The object appeared to be massive, but seemed to be deliberately concealed by the cloud cover of the late evening.Finally, I believe it is important to note that my two friends and I instantaneously grabbed one another by the sleeves of our jackets and stepped backwards, and all of us admitted to immediately feeling a sense of fear and dread, like you sometimes experience when in the woods and you feel like an animal or another person is nearby but you can't see them. (I don't say this for dramatic effect, and I don't want to appear sensationalist, I just think it's important to note the immediate sensory reactions we experienced when we saw these lights.) They did not return after their second episodic light show, but the cloud cover over downtown Portland did seem noticeably brighter than before.