Hi, ahoy, this is a nice piece of glass. It is highly unusual. I have not seen this piece or this mark exactly before but it is a good match for Skrdlovice pattern number 8025/28 by Jan Exnar. According to the books it should be horizontal on display. This can be seen in the pattern books on the Pardubice museum website. As the piece could have been made in 1979, appearing in the 1980 year in the pattern book, this would make "79" impressed on the bottom of the vase make sense. Also "E" for Exnar makes sense. He still signs glass sometimes now as "Ex". I have not seen this impressed mark before, it could have been something Exnar was doing for unique pieces at the time. As this is a "plastika", sculpture, in the books, it would possibly be unikat, not normal production, a series of five or less. Jan Exnar is still alive, perhaps it is possible for you to contact him directly....? This could confirm things. Also, Mr Svoboda is often at his factory in Karlov, he would have been present at the time. Good luck, it is a nice piece of glass!
Robert (bOBA)