Use laptop as a second monitor

I've spent far too much time Googling this and haven't been able to find anything.

I have a laptop and tower both running Ubuntu. I want to be able to use the laptop as a 2nd display to extend the tower's desktop.

The end goal being to have the tower showing Netlfix on 1 screen and a game on the laptop screen.

Is this do-able?

I actually figured this out in a very simple way.

I connected a 2nd HDMI cable from the tower to the 2nd HDMI port on the screen. Ubuntu recognises the extra connection as a 2nd screen and extends the desktop.

Remoting in with TeamViewer then gives me the option to switch between 2 monitors.