To everyone taking a look at this mystery of the universe! My theory… the leaves fall on the surface of this mud pond and it is on a level surface until the sun and air go to work evaporating the moisture in the mud which begins a process of shrinkage, settling and lowering the overall surface level of the pond EXCEPT where the leaves have fallen … with each leaf holding the moisture in the mud just below it so that over a series of days the result is leaf sized mud plugs left at a higher elevation then the rest of the pond… not sure how to prove it but this seems plausible to my intuitive sense of this odd display.