There is a new theme set available on Gnome Look. This makes Linux look just like Macintosh OSX High Sierra. It is very high quality and well worth installing.
The GTK3 theme: https://dl.opendesktop.org/api/files/download/id/1537895905/s/a13d96c5494b48d7c715859105db2c5d/t/1537916795/u//Sierra-light.tar.xz.
Cursor theme: https://dl.opendesktop.org/api/files/download/id/1517130771/s/a13d96c5494b48d7c715859105db2c5d/t/1537916795/u//MacOSX-cursors.tar.xz.
A couple of Mac OSX wallpapers: https://dl.opendesktop.org/api/files/download/id/1517131134/s/a13d96c5494b48d7c715859105db2c5d/t/1537916795/u//HighSierra-wallpapers.tar.xz.
Unpack the GTK theme under the ~/.themes folder. And the icon theme under the ~/.icons folder. Then go to System->Preferences->Look and Feel->Appearance and select the themes with the Customize option. Then the MATE desktop will look like this. It really is very attractive and clean for a desktop theme.
It is one of the best looking themes for Linux. I highly recommend installing it and themeing your MATE desktop to look just like a modern MacOS 10.12.6 machine, and that is pretty cool indeed.
Compare it to the real thing. And notice it just exactly the same. That is how well the theme was made.
Use the MATE Tweak tool to set the window buttons to the left. This completes the look.