fact: Fixpoint half_tile (l : list bool) := match l with | nil => nil | b::l => PUSH x b :: half_tile l end.
imports: List Arith Lia Bool Undecidability.Shared.Libs.DLW(utils list_bool pos vec subcode sss) Undecidability.StackMachines.BSM(tiles_solvable bsm_defs)