This is just one motif of this Stawasz table mat on Page 27 of his Tatted Treasures book. I am not tatting the mat but I love the design it made with this motif.
The top is tatted in Altin Basak SIze 50 thread in Col. #367. I miscounted the number of picots in some rings and was not happy with the graduated picots in the chain, so I decided to start again.
The bottom is tatted in Lizbeth Size 40 Mocha Brown Light (#690). Thinking that this thread would form sturdier picots but I think a Size 20 thread would be better for this pattern. Jan Stawasz used a Size 10.