Rosental Studio Line - what pattern?

I picked up these two glasses today. They have these odd oval pieces of glass attached (one is black, the other is purple), then the whole shape is scooped out and polished.
Both glasses have paper labels saying they are Rosenthal, Studio-line, Germany. The one with black is signed twice on the bottom, the other one not at all.
I haven't been able to figure out the pattern name. Help?










Also, how do I get the frosted area clean without wrecking it? Thanks.

 

Thanks Bakersgma - they very well may be. I'll go snooping..........