1    let numberPennies = 23;
2    let info = document.getElementById("info");
3    let feedback = document.getElementById("feedback");
4    let pieces = document.getElementById("pieces");
5    
6    let intro = "<h3>23 Pennies</h3>";
7    intro += "Take turns taking 1, 2, or 3 pennies. ";
8    intro += "Whoever takes the last penny loses. ";
9    info.innerHTML = intro;
10   
11   displayPennies();
12   
13   function displayPennies()
14   {
15     pieces.innerHTML = "";
16     for (let i = 0; i < numberPennies; i++)
17     {
18       let penny = "<div class='penny'></div>";
19       pieces.innerHTML += penny;
20     }
21   }
22   
23   function take(num)
24   {
25     if (num > numberPennies)
26     {
27       feedback.innerHTML = "There aren't enough pennies.";
28       return;
29     }
30     if (num === numberPennies)
31     {
32       feedback.innerHTML = "You took the last penny. You lose.";
33       numberPennies -= num;
34       displayPennies();
35       return;
36     }
37   
38     numberPennies -= num;
39     feedback.innerHTML = "You took " + num;
40     if (num === 1)
41     {
42       feedback.innerHTML += " penny. ";
43     }
44     else
45     {
46       feedback.innerHTML += " pennies. ";
47     }
48   
49     displayPennies();
50     computerTurn();
51   }
52   
53   function computerTurn()
54   {
55     let num;
56   
57     if (numberPennies > 21 && numberPennies < 25)
58     {
59       num = numberPennies - 21;
60     }
61     else if (numberPennies > 17 && numberPennies < 21)
62     {
63       num = numberPennies - 17;
64     }
65     else if (numberPennies > 13 && numberPennies < 17)
66     {
67       num = numberPennies - 13;
68     }
69     else if (numberPennies > 9 && numberPennies < 13)
70     {
71       num = numberPennies - 9;
72     }
73     else if (numberPennies > 5 && numberPennies < 9)
74     {
75       num = numberPennies - 5;
76     }
77     else if (numberPennies > 1 && numberPennies < 5)
78     {
79       num = numberPennies - 1;
80     }
81     else
82     {
83       while (true)
84       {
85         num = Math.floor(Math.random() * 3) + 1;
86         if (num <= numberPennies)
87         {
88           break;
89         }
90       }
91     }
92     if (num === numberPennies)
93     {
94       feedback.innerHTML += "The computer took the last penny. You win.";
95       numberPennies -= num;
96       displayPennies();
97       return;
98     }
99   
100    numberPennies -= num;
101    feedback.innerHTML += "The computer took " + num;
102    if (num === 1)
103    {
104      feedback.innerHTML += " penny. ";
105    }
106    else
107    {
108      feedback.innerHTML += " pennies. ";
109    }
110    displayPennies();
111  }
112