I was traveling north on shields between loveland and fort collins when i noticed something to my right. i slowed down and looked up, and saw a huge triangular craft heading north along with me. i opened all four windows and my sunroof to try to hear something, and heard no noise. came to a stop at the intersection of trilby and shields, and watched the craft slowly turn to the east. i couldn't turn right to follow, as there were cars in the turn lane, and i couldn't get over there. my best memory for the description was a large triangle with large white lights at each tip, multi-colored lights all over the bottom of the craft, with a dome-like circle in the middle of the undercarriage. 8 months later, while outside one evening, i noticed three triangular lights way up in the sky above me, moving to the north very slowly. there were no blinking lights on it, so i knew it wasn't an airplane. i recognized it immediately as the craft i had seen initially.