Can I use my Android phone as a second monitor?

About ten years ago I started using dual monitors. It was amazing. But I switched to using a laptop exclusively and do not have a second monitor. It occurred to me that I have a second screen right next to me (my phone) that I'm not using. Is it possible to use it as a second monitor? I can imagine using it to show a training video while I follow along on my laptop screen. I have a Mac OSX 10.11 and a Samsung Galaxy 6. I have an older iPhone 4S as well.