iPad screen covered in large purple blocks

I turned on my iPad this evening to discover that the screen is covered over by large purple blocks and one white block running horizontally across the screen. It's five or six large horizontal bands that cover the screen from top to bottom and side to side. When I take my Apple cover completely on and off, the purple blocks go away but a faint ghost of the large white block remains along the outer edges where it would horizontally go off the screen.

I can put the magnet portion of the cover on the left (proper) side and the purple blocks act as I describe above, When I remove the cover completely, the large purple blocks return and then disappear after a moment but still leave the white ghosting band if the white block. If I put the cover on incorrectly with the magnet on the right side, the purple and white bands flash over the homescreen but eventually stop.

However nothing I do gets rid of the faint glow of the white block that remains after the purple ones go away.

I'm sure I'm not describing this properly to do it justice but it's the best I can do. I would take a screen shot but I don't know how to do that on an iPad, nor do I know how to upload a screen grab to this forum.

One thing I should add: my daugter knocked the iPad on the floor about three months ago but we've never experienced any problems but today my son told my wife that he was afraid he messed something up with the cover (his words). But I can't see that Apple would sell a magnetized cover that could potentially screw up the screen of an iPad.

Has anyone else experienced this phenomenon?