diff --git a/idl/Sequence.json5 b/idl/Sequence.json5
index 7ec535c..433d3ca 100644
--- a/idl/Sequence.json5
+++ b/idl/Sequence.json5
@@ -4,6 +4,7 @@
     namespace2: "scm",
     facet: "Sequence",
     brief: "an ordered collection of variants",
+    using_doxygen: true,
     doc: [
         "Elements appear in some determinstic order.",
         "Sequence is GC-aware --> elements must be GC-aware"
diff --git a/include/xo/object2/ASequence.hpp b/include/xo/object2/ASequence.hpp
index db12e6b..4c4c806 100644
--- a/include/xo/object2/ASequence.hpp
+++ b/include/xo/object2/ASequence.hpp
@@ -2,7 +2,7 @@
  *
  *  Generated automagically from ingredients:
  *  1. code generator:
- *       [/home/roland/proj/xo-umbrella2/xo-object2/../xo-facet/codegen/genfacet.py]
+ *       [/Users/roland/proj/xo-umbrella2/xo-object2/../xo-facet/codegen/genfacet.py]
  *     arguments:
  *       --input [./idl/Sequence.json5]
  *  2. jinja2 template for abstract facet .hpp file:
@@ -15,29 +15,61 @@
 
 // includes (via {facet_includes})
 #include <xo/gc/GCObject.hpp>
+#include <xo/facet/obj.hpp>
+#include <xo/facet/facet_implementation.hpp>
+#include <xo/facet/typeseq.hpp>
 
 namespace xo {
 namespace scm {
 
+using Copaque = const void *;
+using Opaque = void *;
+
 /**
 Elements appear in some determinstic order.
 Sequence is GC-aware --> elements must be GC-aware
 **/
 class ASequence {
 public:
+    /** @defgroup scm-sequence-type-traits **/
+    ///@{
+    // types
+    /** type for length of a sequence **/
+    using size_type = std::size_t;
+    /** facet for types with GC support **/
+    using AGCObject = xo::mm::AGCObject;
+    ///@}
 
+    /** @defgroup scm-sequence-methods **/
+    ///@{
+    // const methods
+    /** RTTI: unique id# for actual runtime data representation **/
+    virtual int32_t _typeseq() const noexcept = 0;
     /** true iff sequence is empty **/
-    virtual bool is_empty() const noexcept = 0;
-
-
+    virtual bool is_empty(Copaque data) const noexcept = 0;
     /** true iff sequence is finite **/
-    virtual bool is_finite() const noexcept = 0;
-
-
+    virtual bool is_finite(Copaque data) const noexcept = 0;
     /** return element @p index of this sequence **/
-    virtual obj<AGCObject> at(size_type index) const = 0;
+    virtual obj<AGCObject> at(Copaque data, size_type index) const = 0;
 
+    // nonconst methods
+    ///@}
 }; /*ASequence*/
 
+/** Implementation ISequence_DRepr of ASequence for state DRepr
+ *  should provide a specialization:
+ *
+ *    template <>
+ *    struct xo::facet::FacetImplementation<ASequence, DRepr> {
+ *        using Impltype = ISequence_DRepr;
+ *    };
+ *
+ *  then ISequence_ImplType<DRepr> --> ISequence_DRepr
+ **/
+template <typename DRepr>
+using ISequence_ImplType = xo::facet::FacetImplType<ASequence, DRepr>;
+
 } /*namespace scm*/
-} /*namespace xo*/
\ No newline at end of file
+} /*namespace xo*/
+
+/*  */
\ No newline at end of file
diff --git a/src/object2/CMakeLists.txt b/src/object2/CMakeLists.txt
index 644216a..d7df723 100644
--- a/src/object2/CMakeLists.txt
+++ b/src/object2/CMakeLists.txt
@@ -5,6 +5,7 @@ set(SELF_SRCS
     IGCObject_DFloat.cpp
     IGCObject_DInteger.cpp
     IGCObject_DList.cpp
+    ISequence_Any.cpp
     )
 
 xo_add_shared_library4(${SELF_LIB} ${PROJECT_NAME}Targets ${PROJECT_VERSION} 1 ${SELF_SRCS})