Why McDonald’s Cup Lids Have Rectangular Buttons. Each round button on a McDonald’s cup lid is labeled with an abbreviation so workers and customers know which drink is which.

When it comes to shapes, the USF study published in the Journal of Consumer Research found rounded rectangle buttons have higher click rates than those with sharp 90-degree angles.

We finally know what those rectangular 'buttons' on McDonald's drink lids are used for. The Real Purpose Behind the McDonald’s Drink Buttons Has People Losing It Skip to main content ...

This involves adding a large rounded rectangle around buttons and options. This is what happened with the account switcher for Google chat. When you’re looking to switch to a different account.