Previous work has shown that there are two major complexity barriers in the synthesis of fault-tolerant distributed programs: (1) generation of fault-span. the set of states reachable in the presence of faults. and (2) resolving deadlock states. from where the program has no outgoing transitions. https://www.roneverhart.com/Plastic-Gift-Boxes-Gold-5X4X3-5-6-Pack-Bakery-Boxes-With-Base-Lid-Ribbon/