In Android[0], the "back" button on the bottom is a triangle pointing left. The "home" button is a circle. The "show recent apps" button is a square. All are just flat shapes.

Completely unintuitive to anybody that's never used Android before.

Contrast that to the early days of Android where the Back button was a curved arrow, the Home button was an icon of a house, and the Menu button was the hamburger menu people are familiar with, except the lines were thinner.

[0] This may actually vary depending on what phone you have and if the maker changes these, but on my Pixel 6, this is the description.