diff --git a/package.json b/package.json
index b805d84..8c1a5e3 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
     "name": "minesweeper",
-    "version": "0.0.4",
+    "version": "0.0.5",
     "description": "Just Minesweeper!",
     "author": "Felix W. Dekker",
     "browser": "dist/bundle.js",
diff --git a/src/main/js/index.js b/src/main/js/index.js
index 4e64aa2..332d566 100644
--- a/src/main/js/index.js
+++ b/src/main/js/index.js
@@ -2,7 +2,7 @@ import {$, doAfterLoad, footer, header, nav} from "@fwdekker/template";
 import {MersenneTwister19937, Random} from "random-js";
 
 
-const logArea = document.getElementById("logArea");
+const logArea = $("#logArea");
 const log = (message) => {
     logArea.value += `${message}\n`;
     logArea.scrollTop = logArea.scrollHeight;
@@ -17,12 +17,12 @@ class Game {
      * Constructs and starts a new game of Minesweeper.
      */
     constructor() {
-        this.canvas = document.getElementById("canvas");
-        this.settingsForm = document.getElementById("settingsForm");
-        this.widthInput = document.getElementById("settingsWidth");
-        this.heightInput = document.getElementById("settingsHeight");
-        this.minesInput = document.getElementById("settingsMines");
-        this.seedInput = document.getElementById("settingsSeed");
+        this.canvas = $("#canvas");
+        this.settingsForm = $("#settingsForm");
+        this.widthInput = $("#settingsWidth");
+        this.heightInput = $("#settingsHeight");
+        this.minesInput = $("#settingsMines");
+        this.seedInput = $("#settingsSeed");
 
         this.reset();
         this.display = new Display(this.canvas, this.field);
@@ -116,7 +116,7 @@ class Display {
     constructor(canvas, field) {
         // TODO Remove this \/
         this.frameNumber = 0;
-        this.counter = document.getElementById("counter");
+        this.counter = $("#counter");
         window.setInterval(() => {
             this.counter.innerText = "" + (this.frameNumber * 4);
             this.frameNumber = 0;
@@ -198,7 +198,7 @@ class Display {
         ctx.textBaseline = "middle";
         ctx.textAlign = "center";
         this.field.cellList.forEach(cell => {
-            const neighborMineCount = cell.getNeighborMineCount();
+            const neighborMineCount = cell.getNeighborCount(it => it.hasMine);
             let contents;
             if (cell.isCovered) {
                 if (cell.hasFlag)
@@ -260,6 +260,7 @@ class Field {
     constructor(width, height, mineCount, seed = undefined) {
         this.width = width;
         this.height = height;
+        this.mineCount = mineCount;
 
         const mines = Array(width * height).fill(true, 0, mineCount).fill(false, mineCount);
         shuffleArrayInPlace(mines, seed);
@@ -268,6 +269,18 @@ class Field {
         this.cells = chunkifyArray(this.cellList, this.width);
     }
 
+    /**
+     * Returns a deep copy of this field.
+     *
+     * @return {Field} a deep copy of this field
+     */
+    copy() {
+        const copy = new Field(this.width, this.height, this.mineCount, undefined);
+        copy.cellList = this.cellList.map(it => it.copy());
+        copy.cellList.forEach(it => it.field = copy);
+        copy.cells = chunkifyArray(copy.cellList, copy.width);
+    }
+
 
     /**
      * Returns the cell at the given coordinates, or throws an error if there is no cell there.
@@ -296,16 +309,23 @@ class Field {
         return row === undefined ? orElse : row[y];
     }
 
+
     /**
      * Returns `true` if and only if all mineless cells have been uncovered.
      *
      * @return `true` if and only if all mineless cells have been uncovered
      */
     isCleared() {
-        return this.cellList.reduce(
-            (isCleared, cell) => isCleared && (!cell.isCovered || cell.hasMine),
-            true
-        );
+        return this.cellList.find(it => !it.hasMine && it.isCovered) !== undefined;
+    }
+
+    /**
+     * Returns `true` if and only if a mine has been uncovered.
+     *
+     * @returns {boolean} if and only if a mine has been uncovered
+     */
+    isFailed() {
+        return this.cellList.find(it => it.hasMine && !it.isCovered) !== undefined;
     }
 }
 
@@ -331,6 +351,18 @@ class Cell {
         this.hasFlag = false;
     }
 
+    /**
+     * Returns a deep copy of this cell, without a reference to any field.
+     *
+     * @returns {Cell} a deep copy of this cell, without a reference to any field
+     */
+    copy() {
+        const copy = new Cell(undefined, this.x, this.y, this.hasMine);
+        copy.isCovered = this.isCovered;
+        copy.hasFlag = this.hasFlag
+        return copy;
+    }
+
 
     /**
      * Returns the `Cell`s that are adjacent to this cell.
@@ -351,21 +383,13 @@ class Cell {
     }
 
     /**
-     * Returns the number of neighbors that have a flag.
+     * Returns the number of neighbors that satisfy the given property.
      *
-     * @returns {number} the number of neighbors that have a flag
+     * @param property {function} the property to check on each neighbor
+     * @returns {number} the number of neighbors that satisfy the given property
      */
-    getNeighborFlagCount() {
-        return this.getNeighbors().filter(it => it.hasFlag).length;
-    }
-
-    /**
-     * Returns the number of neighbors that have a mine.
-     *
-     * @returns {number} the number of neighbors that have a mine
-     */
-    getNeighborMineCount() {
-        return this.getNeighbors().filter(it => it.hasMine).length;
+    getNeighborCount(property) {
+        return this.getNeighbors().filter(property).length;
     }
 
 
@@ -375,7 +399,7 @@ class Cell {
      */
     chord() {
         if (this.isCovered) return;
-        if (this.getNeighborMineCount() !== this.getNeighborFlagCount()) return;
+        if (this.getNeighborCount(it => it.hasFlag) !== this.getNeighborCount(it => it.hasMine)) return;
 
         this.getNeighbors()
             .filter(it => it.isCovered && !it.hasFlag)
@@ -397,7 +421,7 @@ class Cell {
         }
 
         this.getNeighbors()
-            .filter(it => it.getNeighborMineCount() === 0 && !it.hasMine && !it.hasFlag)
+            .filter(it => it.getNeighborCount(it => it.hasMine) === 0 && !it.hasMine && !it.hasFlag)
             .forEach(it => it.uncover());
     }
 
@@ -418,7 +442,7 @@ class Cell {
 
         this.isCovered = false;
         this.hasFlag = false;
-        if (!this.hasMine && this.getNeighborMineCount() === 0)
+        if (!this.hasMine && this.getNeighborCount(it => it.hasMine) === 0)
             this.chord();
     }
 }
@@ -477,7 +501,7 @@ doAfterLoad(() => {
 
     // Initialize game
     const urlParams = new URLSearchParams(window.location.search);
-    document.getElementById("settingsSeed").value =
+    $("#settingsSeed").value =
         urlParams.get("seed") === null
             ? "" + Math.floor(Math.random() * 1000000000000)
             : urlParams.get("seed");