diff --git a/src/core_ffi/python_ffi/binder/cases.cc b/src/core_ffi/python_ffi/binder/cases.cc
index 3a1eccb..8300caf 100644
--- a/src/core_ffi/python_ffi/binder/cases.cc
+++ b/src/core_ffi/python_ffi/binder/cases.cc
@@ -1,13 +1,16 @@
 #include "binder.h"
 
-void bind_cases(const py::module_ &m) {
-    py::class_<PyCases>(m, "Cases")
+void bind_cases(const py::module_ &mod) {
+    py::class_<PyCases>(mod, "Cases")
         .def(py::self == py::self)
         .def("__len__", &PyCases::size)
         .def("__repr__", &PyCases::repr)
         .def("__getitem__", &PyCases::at)
-        .def("__iter__", &PyCases::codes, py::keep_alive<0, 1>());
+        .def("__iter__", &PyCases::iter, py::keep_alive<0, 1>())
+        .def_property_readonly_static("all_cases", [](const py::object&) {
+            return PyCases::all_cases();
+        });
 
-    py::class_<PyCasesIter>(m, "CasesIter")
+    py::class_<PyCasesIter>(mod, "CasesIter")
         .def("__next__", &PyCasesIter::next);
 }
diff --git a/src/core_ffi/python_ffi/include/binder.h b/src/core_ffi/python_ffi/include/binder.h
index 237491e..5d62e9d 100644
--- a/src/core_ffi/python_ffi/include/binder.h
+++ b/src/core_ffi/python_ffi/include/binder.h
@@ -20,7 +20,7 @@ using klotski::ffi::PyGroupUnion;
 using klotski::ffi::PyGroup;
 using klotski::ffi::PyFastCal;
 
-void bind_cases(const py::module_ &m);
+void bind_cases(const py::module_ &mod);
 void bind_short_code(const py::module_ &m);
 void bind_common_code(const py::module_ &m);
 
diff --git a/src/core_ffi/python_ffi/include/py_ffi/cases.h b/src/core_ffi/python_ffi/include/py_ffi/cases.h
index 96380af..75fe1b0 100644
--- a/src/core_ffi/python_ffi/include/py_ffi/cases.h
+++ b/src/core_ffi/python_ffi/include/py_ffi/cases.h
@@ -3,7 +3,8 @@
 #pragma once
 
 #include <variant>
-#include <ranges/ranges.h>
+
+#include "ranges/ranges.h"
 
 #include "py_ffi/common_code.h"
 
@@ -14,14 +15,14 @@ using cases::RangesUnion;
 class PyCasesIter {
 public:
     /// Construct from RangesUnion reference.
-    explicit PyCasesIter(const RangesUnion &data);
+    explicit PyCasesIter(const RangesUnion &data) noexcept;
 
-    /// Get the next CommonCode or throw a stop_iteration exception.
+    /// Get the next CommonCode or throw `stop_iteration` exception.
     PyCommonCode next();
 
 private:
-    uint8_t head_ {0};
-    uint32_t index_ {0};
+    size_t index_ {0};
+    uint64_t head_ {0};
     const RangesUnion &data_;
 };
 
@@ -29,8 +30,6 @@ class PyCases {
 public:
     PyCases() = delete;
 
-    // TODO: add `all_cases` interface
-
     // ------------------------------------------------------------------------------------- //
 
     /// Constructing from r-value.
@@ -45,18 +44,21 @@ public:
     [[nodiscard]] size_t size() const noexcept;
 
     /// Get CommonCode iterator of cases.
-    [[nodiscard]] PyCasesIter codes() const noexcept;
+    [[nodiscard]] PyCasesIter iter() const noexcept;
 
     /// Get the CommonCode of the specified index.
-    [[nodiscard]] PyCommonCode at(size_t index) const; // TODO: allow `-1` index
+    [[nodiscard]] PyCommonCode at(int32_t index) const;
 
     // ------------------------------------------------------------------------------------- //
 
+    /// Export all klotski cases.
+    static PyCases all_cases() noexcept;
+
     /// Wrapper of `__repr__` method in Python.
     static std::string repr(const PyCases &cases) noexcept;
 
     /// Compare the cases contents of two PyCases.
-    friend constexpr auto operator==(const PyCases &lhs, const PyCases &rhs);
+    friend constexpr auto operator==(const PyCases &lhs, const PyCases &rhs) noexcept;
 
     // ------------------------------------------------------------------------------------- //
 
@@ -75,7 +77,7 @@ private:
     // ------------------------------------------------------------------------------------- //
 };
 
-constexpr auto operator==(const PyCases &lhs, const PyCases &rhs) {
+constexpr auto operator==(const PyCases &lhs, const PyCases &rhs) noexcept {
     return lhs.data_ref() == rhs.data_ref();
 }
 
diff --git a/src/core_ffi/python_ffi/wrapper/cases.cc b/src/core_ffi/python_ffi/wrapper/cases.cc
index d00feff..8fae0c3 100644
--- a/src/core_ffi/python_ffi/wrapper/cases.cc
+++ b/src/core_ffi/python_ffi/wrapper/cases.cc
@@ -6,17 +6,16 @@
 namespace py = pybind11;
 
 using namespace klotski::ffi;
+using klotski::cases::AllCases;
 
 // ----------------------------------------------------------------------------------------- //
 
-PyCasesIter::PyCasesIter(const RangesUnion &data) : data_(data) {}
+PyCasesIter::PyCasesIter(const RangesUnion &data) noexcept : data_(data) {}
 
 PyCommonCode PyCasesIter::next() {
     while (head_ < 16) {
-        const auto &ranges = data_.ranges(head_);
-        if (index_ < ranges.size()) {
-            auto code = (static_cast<uint64_t>(head_) << 32) | ranges[index_++];
-            return std::bit_cast<PyCommonCode>(code);
+        if (const auto &ranges = data_.ranges(head_); index_ < ranges.size()) {
+            return std::bit_cast<PyCommonCode>((head_ << 32) | ranges[index_++]);
         }
         index_ = 0, ++head_;
     }
@@ -26,36 +25,26 @@ PyCommonCode PyCasesIter::next() {
 // ----------------------------------------------------------------------------------------- //
 
 size_t PyCases::size() const noexcept {
-    size_t num = 0;
-    for (const auto &x : data_ref()) { // TODO: fetch from RangesUnion.size()
-        num += x.size();
-    }
-    return num;
+    return data_ref().size();
 }
 
-PyCasesIter PyCases::codes() const noexcept {
+PyCasesIter PyCases::iter() const noexcept {
     return PyCasesIter(data_ref());
 }
 
-PyCommonCode PyCases::at(size_t index) const {
-    if (index >= size()) {
+PyCommonCode PyCases::at(const int32_t index) const {
+    const auto size_ = static_cast<int32_t>(size());
+    if (index >= size_ || index < -size_) {
         throw py::index_error("cases index out of range");
     }
+    const auto code = data_ref()[index < 0 ? index + size_ : index];
+    return std::bit_cast<PyCommonCode>(code);
+}
 
-    uint64_t head = 0;
-    for (;;) {
-        if (index >= data_ref().ranges(head).size()) {
-            index -= data_ref().ranges(head).size();
-            ++head;
-        } else {
-            break;
-        }
-    }
-    uint32_t range = data_ref().ranges(head)[index];
+// ----------------------------------------------------------------------------------------- //
 
-    // TODO: fetch from RangesUnion[]
-    const auto code = CommonCode::unsafe_create(head << 32 | range);
-    return std::bit_cast<PyCommonCode>(code);
+PyCases PyCases::all_cases() noexcept {
+    return from_ref(AllCases::instance().fetch());
 }
 
 std::string PyCases::repr(const PyCases &cases) noexcept {