To my amazement, this worked for me too. Thanks msichala!
For future readers, here's what was happening to me. This morning, I turned on my phone and it had vertical stripes. The stripes were wide, and alternated between lighter and darker in color. At the same time, touch responsiveness was very buggy. The phone would take 2-3 seconds to respond to a touch, then would respond to multiple touches that I did not make. I tried restarting the phone, but the problem did not go away.
Somehow I managed to open the Settings and get to Accessibility. It took awhile because of the buggy responsiveness of the touch screen. Once there, I toggled both invert colors and gray scale.
The problem went away immediately and the phone has worked fine for the last several hours. Fingers crossed the fix sustains.