Croix de 36
The name is french and means 36 Cross.
This cross was designed in order to have as few holes as possible. It's got 8.
It has so many different pieces that Burrtools is unable to find the solution. The remaining time displayed is "ages". This happens for estimated times greater than 1 million years.
It follows that if the solution sheet was destroyed, disassembling the puzzle would become a physically irreversible process !
Croix de 36 designs