a) In Artua we always start with the search of the most obvious and clear visual metaphor for each icon.
b) Then, we always pay as much attention as possible to each pixel to look ideal on every device.
c) Our goal is to design each icon from scratch to perfectly fit our client's and user's needs.
One of the goals was to fit the icons into the interface. When the work on the icons started, the interface was already complete. So we made the icons stand out, and at the same time, be an integral part of the interface.
And now you can tap the Music icon and start listening to your favorite songs while putting groceries into your fridge.