I have an Oscar Zverzina "Plasticca" "Kunst objektiv" (Art lens), 210mm, which I haven't used much because it seems too sharp in the center for my purposes.
So, I tried an experiment, reversing the position of the meniscus. These images are the center 24x36mm of the image:
|Oscar Zverzina "Plasticca", normal element position|
|Oscar Zverzina "Plasticca", elements reversed in barrel|
I'll certainly use mine in the reversed position. Nice diffusion...