3 triangles hovering over I-70

I was driving eastbound on I-70 in a somewhat rural area. I was talking on the phone and idly looked up at the sky and noticed what looked like 3 perfectly triangular clouds. It was somewhat overcast / partly cloudy, and these 3 perfect triangles were in front of the overcast sky - the same color/texture as the clouds. However, what caught my eye was that they were perfectly sharp/straight, identical in size, and equal distance apart as well as not moving. I was so puzzled and kept blinking and trying to adjust my eyes because it made no sense to see such perfectly straight, sharply angled geometric clouds. It was impossible.
The middle triangle began to sort of dim, almost like a flicker, and then all three of them disappeared instantly. They did not fly away, they did not blow away - these 3 triangles completely disappeared in the blink of an eye.
I was left feeling deeply confused, fearful, and in shock - it is hard to explain in words what I saw, because it is not consistent with anything I have ever seen before. Whatever those triangles were, they were not clouds. They were defying nature.
My sister was on the phone with me the whole time I experienced it. Once I started to realize what they were, I pulled out my camera - I tried pushing a button to record but it would not record. I may have been too shaky and in shock to take my eyes off of it and get my phone recording, though - I wish I was able to capture evidence so I wouldn’t feel so crazy.