Two overlapping radial grads with two lots of corner to corner

This started as two radial gradients in opposite corners of the image. When these are given poster edges one gets two series of concentric rings which are overlapping. This was then given a moderate 'distort - twirl' Then.using 'Image - transform -skew', on a copied layer, one corner was taken over to a neighbouring corner and that corner was taken to the first corner. This achieves a bow-tie effect. This was done between the two right-hand corners initially and then the two top ones. The range of color gradient maps in PSE were applied until this one came out as the best option. The lens correction filter was used to give the concave sides.