diff --git a/package.json b/package.json
index 7821dc1..0f0ce9a 100644
--- a/package.json
+++ b/package.json
@@ -17,6 +17,7 @@
     "bootstrap": "4.5.3",
     "classnames": "^2.3.1",
     "cron": "^1.8.2",
+    "fast-deep-equal": "^3.1.3",
     "froebel": "^0.21.3",
     "lokijs": "^1.5.12",
     "markdown-to-jsx": "^7.1.3",
diff --git a/src/games/games.tsx b/src/games/games.tsx
index 28563f0..6a744db 100644
--- a/src/games/games.tsx
+++ b/src/games/games.tsx
@@ -5,6 +5,7 @@ import UnisexNounGame from "./sub-cores/UnisexNounGame";
 import EquativeSituations from "./sub-cores/EquativeSituations";
 import VerbSituations from "./sub-cores/VerbSituations";
 import EquativeIdentify from "./sub-cores/EquativeIdentify";
+import VerbFormulas from "./sub-cores/VerbFormulas";
 
 // NOUNS
 export const nounGenderGame1 = makeGameRecord({
@@ -270,6 +271,13 @@ export const verbSituationsGame = makeGameRecord({
     level: "situations",
     SubCore: VerbSituations,
 });
+export const verbFormulasGame = makeGameRecord({
+    title: "Choose the verb tense formula",
+    id: "verb-tense-formulas",
+    link: "/verbs/master-chart/",
+    level: "all",
+    SubCore: VerbFormulas,
+});
 
 const games: { chapter: string, items: GameRecord[] }[] = [
     {
@@ -322,6 +330,7 @@ const games: { chapter: string, items: GameRecord[] }[] = [
             allVerbGame1,
             allVerbGame2,
             verbSituationsGame,
+            verbFormulasGame,
         ],
     },
 ];
diff --git a/src/games/sub-cores/VerbFormulas.tsx b/src/games/sub-cores/VerbFormulas.tsx
new file mode 100644
index 0000000..fdcaa56
--- /dev/null
+++ b/src/games/sub-cores/VerbFormulas.tsx
@@ -0,0 +1,285 @@
+import GameCore from "../GameCore";
+import {
+    humanReadableVerbForm,
+    Types as T,
+    InlinePs,
+    grammarUnits,
+    defaultTextOptions as opts,
+} from "@lingdocs/pashto-inflector";
+import { makePool } from "../../lib/pool";
+import { CSSProperties, useEffect, useState } from "react";
+import classNames from "classnames";
+
+const amount = 10;
+const timeLimit = 60;
+
+type StemRoot = "imperfective stem" | "perfective stem" | "imperfective root" | "perfective root";
+type Ending = "present" | "past" | "imperative"; 
+type Formula = {
+    ba: boolean,
+    stemRoot: StemRoot,
+    ending: Ending,
+};
+
+type Question = {
+    tense: T.VerbTense,
+    formula: Formula,
+}
+
+const questions: Question[] = [
+    {
+        tense: "presentVerb",
+        formula: {
+            ba: false,
+            stemRoot: "imperfective stem",
+            ending: "present",
+        },
+    },
+    {
+        tense: "subjunctiveVerb",
+        formula: {
+            ba: false,
+            stemRoot: "perfective stem",
+            ending: "present",
+        },
+    },
+    {
+        tense: "imperfectiveFuture",
+        formula: {
+            ba: true,
+            stemRoot: "imperfective stem",
+            ending: "present",
+        },
+    },
+    {
+        tense: "perfectiveFuture",
+        formula: {
+            ba: true,
+            stemRoot: "perfective stem",
+            ending: "present",
+        },
+    },
+    {
+        tense: "imperfectivePast",
+        formula: {
+            ba: false,
+            stemRoot: "imperfective root",
+            ending: "past",
+        },
+    },
+    {
+        tense: "perfectivePast",
+        formula: {
+            ba: false,
+            stemRoot: "perfective root",
+            ending: "past",
+        },
+    },
+    {
+        tense: "habitualImperfectivePast",
+        formula: {
+            ba: true,
+            stemRoot: "imperfective root",
+            ending: "past",
+        },
+    },
+    {
+        tense: "habitualPerfectivePast",
+        formula: {
+            ba: true,
+            stemRoot: "perfective root",
+            ending: "past",
+        },
+    },
+];
+
+export default function VerbFormulas({ inChapter, id, link, level }: { inChapter: boolean, id: string, link: string, level: "all" }) {
+    const questionsPool = makePool(questions);
+    function getQuestion() {
+        return questionsPool();
+    }    
+    function Instructions() {
+        return <p className="lead">Pick the formula for each verb tense</p>;
+    }
+
+    return <GameCore
+        inChapter={inChapter}
+        studyLink={link}
+        getQuestion={getQuestion}
+        id={id}
+        Display={Display}
+        DisplayCorrectAnswer={DisplayCorrectAnswer}
+        timeLimit={timeLimit}
+        amount={amount}
+        Instructions={Instructions}
+    />
+};
+
+function Display({ question, callback }: QuestionDisplayProps<Question>) {
+    const [ba, setBa] = useState<boolean>(false);
+    const [stemRoot, setStemRoot] = useState<StemRoot | "">("");
+    const [ending, setEnding] = useState<Ending | "">("");
+    useEffect(() => {
+        setBa(false);
+        setStemRoot("");
+        setEnding("");
+    }, [question]);
+    const canSubmit = !!(stemRoot && ending);
+    function handleSubmit() {
+        const { formula } = question;
+        callback(
+            (ba === formula.ba)
+            &&
+            (stemRoot === formula.stemRoot)
+            &&
+            (ending === formula.ending)
+        );
+    }
+    return <div>
+        <div className="my-4" style={{ maxWidth: "300px", margin: "0 auto" }}>
+            <p className="lead">
+                {humanReadableVerbForm(question.tense)}
+            </p>
+        </div>
+        <div className="text-center mb-2">
+            <BaPicker hasBa={ba} onChange={setBa} />
+            <RootsAndStemsPicker stemRoot={stemRoot} onChange={setStemRoot} />
+            <EndingPicker ending={ending} onChange={setEnding} />
+            <button
+                className="btn btn-primary my-2"
+                disabled={!canSubmit}
+                onClick={canSubmit ? handleSubmit : undefined}
+            >
+                Submit
+            </button>
+        </div>
+        <samp>{canSubmit ? printFormula({ ba, stemRoot, ending }) : " "}</samp>
+    </div>
+}
+
+function printFormula(f: Formula): string {
+    return `${f.ba ? "ba + " : ""}${f.stemRoot} + ${f.ending} ending`;
+}
+
+function DisplayCorrectAnswer({ question }: { question: Question }): JSX.Element {
+    return <div>
+        <samp>{printFormula(question.formula)}</samp>
+    </div>;
+}
+
+function EndingPicker({ onChange, ending }: { ending: Ending | "", onChange: (e: Ending | "") => void }) {
+    const options: { label: string, value: Ending }[] = [
+        { label: "Present", value: "present" },
+        { label: "Past", value: "past" },
+        { label: "Imperative", value: "imperative" },
+    ];
+    function handleClick(e: Ending) {
+        // onChange(ending === e ? "" : e);
+        onChange(e);
+    }
+    return <div className="my-3">
+        <span className="mr-2">Ending:</span> 
+        <div className="btn-group">
+            {options.map((option) => (
+                <button
+                    key={option.value}
+                    type="button"
+                    className={classNames(
+                        "btn",
+                         "btn-outline-secondary",
+                        { active: ending === option.value },
+                    )}
+                    onClick={() => handleClick(option.value)}
+                >
+                    {option.label}
+                </button>
+            ))}
+        </div>
+    </div>;
+}
+
+function BaPicker({ onChange, hasBa }: { hasBa: boolean, onChange: (b: boolean) => void }) {
+    return <div className="form-check my-3" style={{ fontSize: "larger" }}>
+        <input
+            id="baCheckbox"
+            className="form-check-input"
+            type="checkbox"
+            checked={hasBa}
+            onChange={e => onChange(e.target.checked)}
+        />
+        <label className="form-check-label text-muted" htmlFor="baCheckbox">
+            with <InlinePs opts={opts}>{grammarUnits.baParticle}</InlinePs> in the kids' section
+        </label>
+    </div>
+}
+
+function RootsAndStemsPicker({ onChange, stemRoot }: { stemRoot: StemRoot | "", onChange: (s: StemRoot | "" ) => void }) {
+    const colClass = "col col-md-5 px-0 mb-1";
+    const rowClass = "row justify-content-between";
+    const title: CSSProperties = {
+        fontWeight: "bolder",
+        paddingBottom: "1.75rem",
+        paddingTop: "1.75rem",
+    };
+    const highlight = {
+        background: "rgba(255, 227, 10, 0.6)",
+    };
+    function handleStemRootClick(s: StemRoot) {
+        onChange(stemRoot === s ? "" : s);
+    }
+    return <div className="verb-info" style={{
+        textAlign: "center",
+        maxWidth: "400px",
+        margin: "0 auto", 
+        // backgroundImage: `url(${fadedTree})`,
+        backgroundRepeat: "no-repeat",
+        backgroundPosition: "50% 45%",
+        backgroundSize: "50%",    
+    }}>
+        <div style={{
+            border: "2px solid black",
+            padding: "1rem",
+            margin: "0.25rem",
+        }} className="container">
+            <div className={rowClass + " align-items-center"}>
+                <div className={colClass}>
+                    <i className="fas fa-video fa-lg" />
+                </div>
+                <div className={colClass}>
+                    <div className="d-flex flex-row justify-content-center align-items-center">
+                        <div>
+                            <i className="fas fa-camera fa-lg mx-3" />
+                        </div>
+                    </div>
+                </div>
+            </div>
+            <div className={rowClass}>
+                <div className={colClass} style={stemRoot === "imperfective stem" ? highlight : {}}>
+                    <div className="clickable" style={title} onClick={() => handleStemRootClick("imperfective stem")}>
+                        <div>Imperfective Stem</div>
+                    </div>
+                </div>
+                <div className={colClass} style={stemRoot === "perfective stem" ? highlight : {}}>
+                    <div className="clickable" style={title} onClick={() => handleStemRootClick("perfective stem")}>
+                        <div>Perfective Stem</div>
+                    </div>
+                </div>
+            </div>
+            <div className={rowClass}>
+                <div className={colClass} style={stemRoot === "imperfective root" ? highlight : {}}>
+                    <div className="clickable" style={title} onClick={() => handleStemRootClick("imperfective root")}>
+                        <div>Imperfective Root</div>
+                    </div>
+                </div>
+                <div className={colClass} style={stemRoot === "perfective root" ? highlight : {}}>
+                    <div>
+                        <div className="clickable" style={title} onClick={() => handleStemRootClick("perfective root")}>
+                            <div>Perfective Root</div>
+                        </div>
+                    </div>
+                </div>
+            </div>
+        </div>
+    </div>;
+}
+
diff --git a/src/lib/pool.ts b/src/lib/pool.tsx
similarity index 88%
rename from src/lib/pool.ts
rename to src/lib/pool.tsx
index 11c365a..2dc3248 100644
--- a/src/lib/pool.ts
+++ b/src/lib/pool.tsx
@@ -1,4 +1,5 @@
 import { randFromArray } from "@lingdocs/pashto-inflector";
+import equal from "fast-deep-equal";
 
 /**
  * 
@@ -22,7 +23,7 @@ export function makePool<P>(poolBase: P[], removalLaxity = 0): () => P {
         if (shouldStillKeepIt()) {
             return pick;
         }
-        const index = pool.findIndex(v => matches(v, pick))
+        const index = pool.findIndex(v => equal(v, pick))
         if (index === -1) throw new Error("could not find pick from pool");
         pool.splice(index, 1);
         // If the pool is empty, reset it
@@ -34,8 +35,3 @@ export function makePool<P>(poolBase: P[], removalLaxity = 0): () => P {
     return pickRandomFromPool;
 }
 
-function matches(a: unknown, b: unknown): boolean {
-    return JSON.stringify(a) === JSON.stringify(b);
-}
-
-
diff --git a/yarn.lock b/yarn.lock
index b42431e..fcb9010 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -5648,7 +5648,7 @@ extsprintf@^1.2.0:
   resolved "https://registry.yarnpkg.com/extsprintf/-/extsprintf-1.4.0.tgz#e2689f8f356fad62cca65a3a91c5df5f9551692f"
   integrity sha1-4mifjzVvrWLMplo6kcXfX5VRaS8=
 
-fast-deep-equal@^3.1.1:
+fast-deep-equal@^3.1.1, fast-deep-equal@^3.1.3:
   version "3.1.3"
   resolved "https://registry.yarnpkg.com/fast-deep-equal/-/fast-deep-equal-3.1.3.tgz#3a7d56b559d6cbc3eb512325244e619a65c6c525"
   integrity sha512-f3qQ9oQy9j2AhBe/H9VC91wLmKBCCU/gDOnKNAYG5hswO7BLKj09Hc5HYNz9cGI++xlpDCIgDaitVs03ATR84Q==