This is the second of these I have seen images for, in two days, one in the US and this one. Your friend has good reason for thinking Czech, as there was a very similar pattern, with the seemingly irregular edge, coming out of Sklo Union Teplice, designed by Panak, from the mid 1970's. I'll try to find the images shortly, but I have a feeling Panak's table-ware did not have the clear centre.
Regards,
Marcus