Charles,
I can see the strong resemblance to Hora's Skrdlovice piece, but I'm pretty sure he didn't design a triangular one. I thought it could be a later version made by Beranek SRO in the 2000's. I know they used the Hora design a lot, and they also used brighter colours, but I can't see it the one Beranek catalogue I looked at. The colours adn oveall effect look more scandinavian to me. Did Kosta do anything like this?
David