The motif is from Ann Orr's Classic Tatting Patterns.
The top one, in green, is the original without a centre. The blue one has interlocking rings in the centre and finally the dark pink has little rings. I also moved where the rings are attached at the base of the onion rings. In the end, I prefer attaching lower as in the green. I may redo the shape of the green with little rings in the centre.
The interlocking rings are interesting but add extra thickness to the tatting which may not be appropriate if you wanted to use the motif to make a doily.
I do like it without a centre but the space is just a little too large for my liking. Just a bit smaller and you could leave that space empty.
What do you think? Do you have a favourite?