[svenfaw]

The same can be done on Android (Lollipop and above).

[neogodless]

I have a fully updated Nexus - if you search Settings for "gray" you get no results. No "direct access" options under Accessibility. Seems like they may have removed it since 7. They do have some color-blind color correction options, but grayscale wasn't something I could find.

ETA: Ah on the "Go gray" page they describe the steps, including enabling Developer Mode first.

[CarVac]

How do you do it in Android?

[svenfaw]

Settings > Accessibility > Direct Access > Grayscale (Tested on Lollipop - may vary on later versions)