Stackable dinnerware prototype 1981

I can't find the designer/potter of this pieces.... they are signed by hand with AST81 or A.ST 81 all of them with a handincised signature just one with a written AST81 or A.ST81.. is this possibly a diploma?

Underneath one of them has been a HfBK Hamburg sticker with a name which i can't remember... unfortunately the seller ripped it off after i have allready bought it and went for some banana boxes... to carry the set away.....

the whole set has been covered in hamburger newspapers from 1981...I add a pics of the incised signatures .....

I really like the concept.... the plates can be used also either as lids for the pots or as coasters.. the drinking pots can be used as lidded pots also....

The little holes are the spouts of the coffee/teapots.... there is a whole set in white glaze and teapots in different colored glaze variations...

three forms to make a mould for other shaped pots has been in one of the bowls and there are several other pieces in another design with the same signature underneath..... three of them are cut in the middle to show the profile of them.....

all this and the HfBK Hamburg sticker has been the reason that i thought these might be prototypes by a member or student of the HfBK.... maybe a product design diploma? I mean a stackable hotel tableware concept in the tradition of the TC 100 by nick roericht, etc....
(The HfBK is the short form of the  "Hochschule für bildende Künste"  University of Arts)