diff --git a/scripts/equivalence.ts b/scripts/equivalence.ts
index cd3703e..035fa54 100644
--- a/scripts/equivalence.ts
+++ b/scripts/equivalence.ts
@@ -1,22 +1,21 @@
-import { mean, round, sortBy } from "lodash-es";
+import { existsSync, readFileSync, writeFileSync } from "fs";
+import { mean, round, sortBy, sum } from "lodash-es";
 import { erf, std } from "mathjs";
+import { exit } from "process";
 import { get } from "~/api";
-import type { EquivalenceData } from "~/lib/equivalence";
+import type { EquivalenceData, Pair } from "~/lib/equivalence";
 import { distance, partition, 手机五行七列 } from "~/lib/equivalence";
 
-const partitions = partition(手机五行七列);
-const hashmap = new Map<string, number>();
-
-for (const [index, set] of partitions.entries()) {
-  for (const v of set) {
-    hashmap.set(`${v.initial},${v.final}`, index);
-  }
+interface Estimation {
+  value: number;
+  std: number;
+  length: number;
 }
 
-interface Measurement {
-  mean: number;
+interface Equivalence {
+  distance: number;
+  value: number;
   std: number;
-  length: number;
 }
 
 // discard outliers using Chauvenet's criterion
@@ -30,13 +29,19 @@ function chauvenet(data: number[]) {
   });
 }
 
-function measure(data: number[]): Measurement {
+function measure(data: number[]): Estimation {
   if (data.length === 0) {
     return {
-      mean: NaN,
+      value: NaN,
       std: NaN,
       length: 0,
     };
+  } else if (data.length === 1) {
+    return {
+      value: data[0]!,
+      std: 0,
+      length: 1,
+    };
   }
   // recursively discard outliers
   let finalData = data;
@@ -46,13 +51,17 @@ function measure(data: number[]): Measurement {
     finalData = newData;
   }
   return {
-    mean: mean(finalData),
-    std: std(finalData, "unbiased") as number,
+    value: mean(finalData),
+    std: (std(finalData, "unbiased") as number) / Math.sqrt(finalData.length),
     length: finalData.length,
   };
 }
 
-function analyze(d: EquivalenceData) {
+function analyze(
+  d: EquivalenceData,
+  partitions: Set<Pair>[],
+  hashmap: Map<string, number>,
+) {
   const { data } = d;
   const result = partitions.map((x) => ({ set: x, data: [] as number[] }));
   for (const { initial, final, time } of data) {
@@ -65,32 +74,107 @@ function analyze(d: EquivalenceData) {
   }
   const stats = result.map(({ set, data }) => {
     const dist = distance([...set][0]!);
-    console.log(dist, data);
     return {
       ...measure(data),
       rawLength: data.length,
       distance: dist,
     };
   });
-  return sortBy(stats, (x) => x.distance);
+  return stats;
 }
 
-const data = await get<EquivalenceData[], undefined>("equivalence");
+function preprocess(modelData: EquivalenceData[]) {
+  const partitions = partition(手机五行七列);
+  const hashmap = new Map<string, number>();
+  for (const [index, set] of partitions.entries()) {
+    for (const v of set) {
+      hashmap.set(`${v.initial},${v.final}`, index);
+    }
+  }
 
-const modelData = data.find((d) => d.model === "手机五行七列")!;
+  const sampleData = partitions.map((x) => ({
+    set: x,
+    data: [] as Equivalence[],
+  }));
 
-const analyzeResult = analyze(modelData);
-for (const { distance, mean, std } of analyzeResult) {
-  console.log(`键距 ${distance}：${round(mean, 2)} ± ${round(std, 2)} ms`);
+  for (const sample of modelData) {
+    // 和 partitions 一一对应
+    const sampleResult = analyze(sample, partitions, hashmap);
+    const baseline = sampleResult.find((x) => x.distance === 0);
+    if (!baseline) continue;
+    sampleResult.forEach(({ distance, value, std }, index) => {
+      if (distance === 0) {
+        sampleData[index]!.data.push({ distance, value: 1, std: 0 });
+      } else {
+        const ratio = value / baseline.value;
+        const correction = 1 + baseline.std ** 2 / baseline.value ** 2;
+        if (correction > 1.0003) console.log(distance, ratio, correction);
+        const ratioStd =
+          Math.sqrt((std / value) ** 2 + (baseline.std / baseline.value) ** 2) *
+          ratio;
+        sampleData[index]!.data.push({
+          distance,
+          value: ratio * correction,
+          std: ratioStd,
+        });
+      }
+    });
+  }
+  return sampleData;
 }
-const baseline = analyzeResult.find((x) => x.distance === 0)!;
-const others = analyzeResult.filter((x) => x.distance !== 0);
 
-for (const { distance, mean, std, rawLength, length } of others) {
-  const quotient = mean / baseline.mean;
-  const qstd = std / baseline.mean;
-  const diff = rawLength - length;
-  console.log(
-    `键距 ${distance}：${round(quotient, 2)} ± ${round(qstd, 2)}（${rawLength} 个样本${diff ? `，${diff} 个无效样本` : ""}）`,
-  );
+function finalize(sampleData: { set: Set<Pair>; data: Equivalence[] }[]) {
+  return sampleData.map(({ set, data }) => {
+    const distance = data[0]!.distance;
+    const values = data.map((x) => x.value);
+    const stds = data.map((x) => x.std);
+    const variances = stds.map((x) => x ** 2);
+    const coefficients = data.map(() => 1 / data.length);
+    // 另一种权重计算方法
+    // const suminvvar = sum(variances.map((x) => 1 / x));
+    // const coefficients = variances.map((x) => 1 / x / suminvvar);
+    const value = sum(values.map((x, j) => x * coefficients[j]!));
+    const variance = sum(variances.map((x, j) => x * coefficients[j]! ** 2));
+    const std = Math.sqrt(variance);
+    const equivalence: Equivalence = { distance, value, std };
+    return { set, ...equivalence };
+  });
+}
+
+let data: EquivalenceData[];
+if (existsSync("scripts/data.json")) {
+  data = JSON.parse(readFileSync("scripts/data.json", "utf-8"));
+} else {
+  const res = await get<EquivalenceData[], undefined>("equivalence");
+  if ("err" in res) exit(1);
+  data = res;
+  writeFileSync("scripts/data.json", JSON.stringify(data, null, 2));
 }
+const modelData = data.filter((d) => d.model === "手机五行七列");
+const sampleData = preprocess(modelData);
+const equivalence = finalize(sampleData);
+const sortedEquivalence = sortBy(equivalence, "distance", "value");
+
+writeFileSync("scripts/equivalence.json", JSON.stringify(sampleData, null, 2));
+
+const content = [["组合", "分组", "当量", "不确定度"].join("\t")];
+const counter = new Map<number, number>();
+for (const { distance, value, std, set } of sortedEquivalence) {
+  let groupname: string;
+  if (distance === -1) {
+    groupname = "/";
+  } else {
+    const distanceCount = counter.get(distance) ?? 0;
+    groupname = `${distance}${"ABCDEFGHIJKLMNOPQRSTUVWXYZ"[distanceCount]}`;
+    counter.set(distance, distanceCount + 1);
+  }
+  for (const { initial, final } of sortBy([...set], "initial", "final")) {
+    content.push(
+      [`${initial}-${final}`, groupname, round(value, 3), round(std, 3)].join(
+        "\t",
+      ),
+    );
+  }
+}
+
+writeFileSync("scripts/手机 5 × 7 当量.txt", content.join("\n") + "\n");
diff --git a/src/components/ResultSummary.tsx b/src/components/ResultSummary.tsx
index c78192e..546813e 100644
--- a/src/components/ResultSummary.tsx
+++ b/src/components/ResultSummary.tsx
@@ -32,6 +32,7 @@ const Customize = ({
   const add = useAddAtom(customizeAtom);
   const addCorner = useAddAtom(customizeCornersAtom);
   const serializer = useAtomValue(serializerAtom);
+  const showCorners = serializer === "c3" || serializer === "snow2";
   return (
     <ProForm<{ content: string[]; corners: CornerSpecifier }>
       title={component}
@@ -63,7 +64,7 @@ const Customize = ({
         )}
       </ProFormList>
       <ProFormGroup>
-        {serializer === "c3" &&
+        {showCorners &&
           range(4).map((i) => (
             <ProFormSelect
               key={i}
diff --git a/src/lib/component.ts b/src/lib/component.ts
index b9a004b..ccfc67d 100644
--- a/src/lib/component.ts
+++ b/src/lib/component.ts
@@ -152,7 +152,10 @@ export const getComponentScheme = function (
       (x) => x & (1 << (component.glyph.length - corner - 1)),
     ),
   ) as CornerSpecifier;
-  if (config.analysis.serializer === "c3") {
+  if (
+    config.analysis.serializer === "c3" ||
+    config.analysis.serializer === "snow2"
+  ) {
     // 根据四角信息对 sequence 进行排序
     // if (sequence.length > 3) {
     //   console.log(component.name, sequence, corners);
@@ -277,6 +280,8 @@ export const recursiveRenderComponent = function (
 };
 
 const overrideCorners: Map<string, CornerSpecifier> = new Map([
+  ["七", [0, 0, 1, 1]],
+  ["九", [0, 0, 1, 1]],
   ["良", [0, 0, 4, 6]],
   ["\uE06A", [0, 0, 4, 5]],
   ["世", [0, 0, 4, 4]],
diff --git a/src/lib/compound.ts b/src/lib/compound.ts
index fc0c865..9ac223c 100644
--- a/src/lib/compound.ts
+++ b/src/lib/compound.ts
@@ -14,6 +14,7 @@ import type {
   CompoundCharacter,
 } from "./data";
 import type { CornerSpecifier } from "./topology";
+import type { Analysis } from "./config";
 
 export type CompoundResults = Map<string, CompoundAnalysis | ComponentAnalysis>;
 
@@ -446,11 +447,41 @@ const zhangmaSerializer: Serializer = (operandResults, glyph) => {
   };
 };
 
-const serializerMap: Record<string, Serializer> = {
+const snow2Serializer: Serializer = (operandResults, glyph) => {
+  const sequence: string[] = [];
+  const corners: CornerSpecifier = [0, 0, 0, 0];
+  const [first, last] = [operandResults[0]!, operandResults.at(-1)!];
+  sequence.push(getTL(first));
+  if (/[⿴⿵⿶⿷⿹⿺⿻]/.test(glyph.operator)) {
+    if (first.corners[0] !== first.corners[3]) {
+      sequence.push(getBR(first, true));
+      corners[3] = 1;
+    } else {
+      sequence.push(getBR(last));
+      corners[3] = 0;
+    }
+  } else {
+    sequence.push(getBR(last));
+    corners[3] = 1;
+  }
+  return {
+    sequence,
+    corners,
+    full: [],
+    operator: glyph.operator,
+    operandResults,
+  };
+};
+
+const serializerMap: Record<
+  Exclude<Analysis["serializer"], undefined>,
+  Serializer
+> = {
   sequential: sequentialSerializer,
   c3: c3Serializer,
   zhangma: zhangmaSerializer,
   zhenma: zhenmaSerializer,
+  snow2: snow2Serializer,
 };
 
 /**
diff --git a/src/lib/config.ts b/src/lib/config.ts
index a418a9f..fc0088f 100644
--- a/src/lib/config.ts
+++ b/src/lib/config.ts
@@ -45,7 +45,7 @@ export interface Analysis {
   customizeCorners?: Record<string, CornerSpecifier>;
   strong?: string[];
   weak?: string[];
-  serializer?: "sequential" | "c3";
+  serializer?: "sequential" | "c3" | "zhangma" | "zhenma" | "snow2";
 }
 
 export interface Degenerator {
diff --git a/src/lib/equivalence.ts b/src/lib/equivalence.ts
index e847fa4..4637b04 100644
--- a/src/lib/equivalence.ts
+++ b/src/lib/equivalence.ts
@@ -24,10 +24,10 @@ export function partition<T>({ group, relation }: Model<T>) {
     const stack = [v];
     while (stack.length > 0) {
       const u = stack.pop()!;
-      if (visited.has(u)) continue;
       visited.add(u);
       subgroup.add(u);
       for (const w of group) {
+        if (visited.has(w)) continue;
         if (relation(u, w)) stack.push(w);
       }
     }
@@ -42,9 +42,15 @@ export interface Pair {
 }
 
 const isDifferentHand = (p: Pair) => {
+  if (p.initial === p.final) return false;
   return (p.initial < 20 && p.final >= 15) || (p.initial >= 15 && p.final < 20);
 };
 
+const isSameHand = (p1: Pair, p2: Pair) => {
+  const numbers = [p1.initial, p1.final, p2.initial, p2.final];
+  return numbers.every((n) => n < 15) || numbers.every((n) => n >= 20);
+};
+
 const reflect = (n: number) => {
   let [col, row] = [Math.floor(n / 5), n % 5];
   return (6 - col) * 5 + row;
@@ -57,6 +63,12 @@ export const distance = (p: Pair) => {
   return (x1 - x2) ** 2 + (y1 - y2) ** 2;
 };
 
+export const displacement = (p: Pair) => {
+  let [x1, y1] = [Math.floor(p.initial / 5), p.initial % 5];
+  let [x2, y2] = [Math.floor(p.final / 5), p.final % 5];
+  return [x2 - x1, y2 - y1] as const;
+};
+
 export const 手机五行七列: Model<Pair> = {
   group: new Set(
     range(35)
@@ -64,16 +76,19 @@ export const 手机五行七列: Model<Pair> = {
       .flat(),
   ),
   relation: (p1, p2) => {
-    return distance(p1) === distance(p2);
-    // // 当量 0
-    // if (isDifferentHand(p1) && isDifferentHand(p2)) return true;
-    // // 当量 1
-    // if (p1.initial === p1.final && p2.initial === p2.final) return true;
-    // // 时间反演
-    // if (p1.initial === p2.final && p1.final === p2.initial) return true;
-    // // 空间镜像
-    // if (reflect(p1.initial) === p2.initial && reflect(p1.final) === p2.final)
-    //   return true;
-    // return false;
+    // 异指连击当量相同
+    if (isDifferentHand(p1) && isDifferentHand(p2)) return true;
+    // 同键连击当量相同
+    if (p1.initial === p1.final && p2.initial === p2.final) return true;
+    // 时间反演
+    if (p1.initial === p2.final && p1.final === p2.initial) return true;
+    // 空间镜像
+    if (reflect(p1.initial) === p2.initial && reflect(p1.final) === p2.final)
+      return true;
+    // 空间平移（同手）
+    const [dx1, dy1] = displacement(p1);
+    const [dx2, dy2] = displacement(p2);
+    if (isSameHand(p1, p2) && dx1 === dx2 && dy1 === dy2) return true;
+    return false;
   },
 };