Unknown icon on radio display

E90 with Sirius and Bluetooth. Saw an icon today for the first time, and can't find any reference to it in the Radio Owners Manual.

It's a Rectangular shaped shaded area with three smaller rectangles inside it forming a sort of pyramid. One on top with two below... touching at the lower corners of the top one.

Anyone ever see this? Know what it is?

Thanks...

Is it cold where you are?

Yes it's about 20 degrees today.

Does it look like this?

  []
[]  []

That's it.