+ unfold mkDropFlags.
+ simpl.
+ unfold flatten_leveled_type.
+ destruct (General.list_eq_dec l' (ec :: nil)); simpl.
+ rewrite e.
+ unfold levels_to_tcode.
+ eapply AComp.
+ apply ACanL.
+ apply AuCanR.
+ eapply AComp.
+ apply ACanR.
+ eapply AComp.
+ apply AuCanL.
+ apply ARight.
+ apply AWeak.
+
+ simpl.
+ apply ARight.
+ apply AWeak.
+
+ drop_simplify.
+ simpl.
+ set (mapOptionTree flatten_leveled_type (drop_lev (ec :: nil) succ2)) as d2 in *.
+ set (mapOptionTree flatten_leveled_type (drop_lev (ec :: nil) succ1)) as d1 in *.
+ set (mapOptionTree flatten_leveled_type (dropT (mkFlags
+ (liftBoolFunc false (bnot ○ levelMatch (ec :: nil))) succ1))) as s1 in *.
+ set (mapOptionTree flatten_leveled_type (dropT (mkFlags
+ (liftBoolFunc false (bnot ○ levelMatch (ec :: nil))) succ2))) as s2 in *.
+ set (mapOptionTree (flatten_type ○ unlev) (dropT (mkFlags
+ (liftBoolFunc true (bnot ○ levelMatch (ec :: nil))) succ1))) as s1' in *.
+ set (mapOptionTree (flatten_type ○ unlev) (dropT (mkFlags
+ (liftBoolFunc true (bnot ○ levelMatch (ec :: nil))) succ2))) as s2' in *.
+
+ eapply AComp.
+ apply arrangeSwapMiddle.
+
+ eapply AComp.
+ eapply ALeft.
+ apply IHsucc2.
+
+ eapply AComp.
+ eapply ARight.
+ apply IHsucc1.
+
+ eapply AComp.
+ apply arrangeSwapMiddle.
+ apply ARight.
+ unfold take_lev.
+ unfold mkTakeFlags.
+
+ unfold s1'.
+ unfold s2'.
+ clear s1' s2'.
+ set (mapOptionTree (flatten_type ○ unlev) (dropT (mkFlags
+ (liftBoolFunc true (bnot ○ levelMatch (ec :: nil))) succ1))) as s1' in *.
+ set (mapOptionTree (flatten_type ○ unlev) (dropT (mkFlags
+ (liftBoolFunc true (bnot ○ levelMatch (ec :: nil))) succ2))) as s2' in *.
+
+ apply (Prelude_error "almost there!").
+ Defined.