The theme settings menu lets you change icon shape, accent color, and font in your older Pixel devices. The first generation Pixel, Pixel 2, and Pixel 3 owners can try this experimental feature right now. Here is how it is. The theme settings menu is hidden in the Developer Options menu. So first, you need to enable the Developer Options in your Pixel device to use the feature. You can change the default circular icons to rounded square icons, teardrop shapes icons, or squircles shape icons. You can also choose any of the seven accent colors for your device instead of the default blue color. Also, you can change the system font if you wish so.