diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
index ed462bc..fdd95e0 100644
--- a/src/core/CMakeLists.txt
+++ b/src/core/CMakeLists.txt
@@ -1,12 +1,11 @@
 cmake_minimum_required(VERSION 3.12)
-project(klotski_core VERSION 0.0.1 LANGUAGES CXX)
+project(klotski_core VERSION 0.0.2 LANGUAGES CXX)
 
 set(CMAKE_CXX_STANDARD 23)
 
 set(KLSK_CORE_SRC
     ranges/internal/spawn.cc
     ranges/internal/ranges.cc
-    ranges/internal/derive.cc
 
     all_cases/internal/basic_ranges.cc
     all_cases/internal/all_cases.cc
diff --git a/src/core/benchmark/ranges.cc b/src/core/benchmark/ranges.cc
index 01bb5f3..f10560a 100644
--- a/src/core/benchmark/ranges.cc
+++ b/src/core/benchmark/ranges.cc
@@ -4,33 +4,69 @@
 #include "ranges/ranges.h"
 #include "all_cases/all_cases.h"
 
+using klotski::cases::Ranges;
 using klotski::cases::AllCases;
 using klotski::cases::BasicRanges;
+using klotski::cases::RangesUnion;
 
-static void SpawnRanges(benchmark::State &state) {
-    // constexpr auto nums = target_nums();
+using klotski::group::BLOCK_NUM;
+using klotski::cases::ALL_CASES_NUM;
+using klotski::cases::BASIC_RANGES_NUM_;
 
-    for (auto _ : state) {
+Ranges ranges_samples(const size_t num) {
+    auto &ranges = BasicRanges::instance().fetch();
+    const size_t part_size = ranges.size() / num;
+    const size_t offset = part_size / 2;
 
-        klotski::cases::Ranges kk {};
-        kk.reserve(7311921);
+    Ranges result;
+    for (size_t i = 0; i < num; ++i) {
+        result.emplace_back(ranges[i * part_size + offset]);
+    }
+    return result;
+}
 
-        // for (uint32_t type_id = 0; type_id < klotski::cases::TYPE_ID_LIMIT; ++type_id) {
-            for (auto [n, n_2x1, n_1x1] : klotski::group::BLOCK_NUM) {
-                kk.spawn(n, n_2x1, n_1x1);
+static void CheckRanges(benchmark::State &state) {
+    auto ranges = ranges_samples(state.range(0));
+    ranges.reverse();
+    for (auto _ : state) {
+        for (const auto range : ranges) {
+            for (const auto head : RangesUnion::Heads) {
+                benchmark::DoNotOptimize(Ranges::check(static_cast<int>(head), range));
             }
-        // }
+        }
     }
-
+    state.SetItemsProcessed(state.iterations() * state.range(0) * 12);
 }
 
-static void RangesReverse(benchmark::State &state) {
+static void ReverseRanges(benchmark::State &state) {
     auto ranges = BasicRanges::instance().fetch();
     for (auto _ : state) {
         ranges.reverse();
     }
 }
 
+static void SpawnRanges(benchmark::State &state) {
+    for (auto _ : state) {
+        Ranges ranges {};
+        ranges.reserve(BASIC_RANGES_NUM_);
+        for (const auto [n, n_2x1, n_1x1] : BLOCK_NUM) {
+            ranges.spawn(n, n_2x1, n_1x1);
+        }
+    }
+}
+
+static void DeriveRanges(benchmark::State &state) {
+    auto ranges = BasicRanges::instance().fetch();
+    ranges.reverse();
+    for (auto _ : state) {
+        RangesUnion cases;
+        for (const auto head : RangesUnion::Heads) {
+            cases.ranges(head).reserve(ALL_CASES_NUM[head]);
+            ranges.derive(static_cast<int>(head), cases.ranges(head));
+        }
+    }
+}
+
 static void RangesUnionExport(benchmark::State &state) {
     auto &all_cases = AllCases::instance().fetch();
     for (auto _ : state) {
@@ -77,14 +113,18 @@ static void RangesAt(benchmark::State &state) {
     }
 }
 
+BENCHMARK(CheckRanges)->Unit(benchmark::kMicrosecond)->Range(16, 256);
+
+// BENCHMARK(ReverseRanges)->Unit(benchmark::kMillisecond);
+
 // BENCHMARK(SpawnRanges)->Unit(benchmark::kMillisecond);
 
-// BENCHMARK(RangesReverse)->Unit(benchmark::kMillisecond);
+// BENCHMARK(DeriveRanges)->Unit(benchmark::kMillisecond);
 
 // BENCHMARK(RangesUnionExport)->Unit(benchmark::kMillisecond);
 
 // BENCHMARK(RangesSize);
 
-BENCHMARK(RangesAt);
+// BENCHMARK(RangesAt);
 
 BENCHMARK_MAIN();
diff --git a/src/core/ranges/internal/derive.cc b/src/core/ranges/internal/derive.cc
deleted file mode 100644
index e960d24..0000000
--- a/src/core/ranges/internal/derive.cc
+++ /dev/null
@@ -1,4 +0,0 @@
-// #include "utils/utility.h"
-// #include "ranges/ranges.h"
-//
-// using klotski::cases::Ranges;