What's this on my Illustrator Artboard?

[keith1]

I'm attaching a screen shot from Illustrator 2015, version 19. Somehow I put these things on there. I haven't a clue how, I've no idea what they are or what they're for, but I'd really like to remove them.
Upper left looks like a cube of sorts. No idea what the thing is on my artwork. There is stuff on the art board but I've turned off the layers so you could see this better. I just want to get rid of it.

While I'm here, another Illustrator question. Customer sent me a file - actually this same one in question. He used the 'Live Paint' feature to fill an area. No idea why. I didn't notice that layer was live paint until I tried to run out a PDF and it wouldn't print properly. Is this usual when having a live paint option?
After having trouble with the PDF I found that layer, got rid of the live paint and used a regular colour fill and solved the PDF problem.
I've never used live paint. Wasn't even aware it existed.

Thanks,
Keith

 

[Sherbert]

Can't see the attachment, but sounds like perspective grid.

"Click View > Perspective Grid > Show Grid. Press Ctrl+Shift+I (on Windows) or Cmd+Shift+I (on Mac) to show the Perspective Grid. The same keyboard shortcut can be used to hide the visible grid. Click the Perspective Grid tool from the Tools panel"

 

[keith1]

Hi Sherbert,

That's what it was alright. I guess I clicked on it inadvertently at some point. There's a lot of features I've never used. I generally use InDesign and had this not been a customer supplied file would have used InDesign for this project. I did hunt around trying to see what I'd done. Didn't hunt enough obviously.

Thank you so much!
Keith