<p>The random number generator could have been seeded with the same seed, which would cause the same sequence of random number to be generated. The RNG in Microsoft's C library repeats every ~32,000 numbers (which is pretty abysmal), so there's effectively only that many seeds.</p>

<p>Different seeds:</p>

<pre><code>&gt;perl -E"say srand; say join ' ', map int(rand(52))+1, 1..10;"
1819759215  # The seed
41 35 23 9 35 2 41 11 50 51

&gt;perl -E"say srand; say join ' ', map int(rand(52))+1, 1..10;"
994223390
47 13 12 51 35 7 37 42 11 2
</code></pre>

<p>But what if the same seed was picked the next day:</p>

<pre><code>&gt;perl -E"srand(994223390); say join ' ', map int(rand(52))+1, 1..10;"
47 13 12 51 35 7 37 42 11 2
</code></pre>

CC BY-SA 3.0
2015-06-29T07:39:47.180Z
2015-06-29T07:45:26.063Z
2015-06-29T07:45:26.063Z
ikegami
<p>For the third time in 5 or 6 games today and yesterday I am seeing the same Spider Solitaire layout that I saw two days go. These three games all had very unique patterns, and took a large number of moves to solve, nearly 5,000 the second time on one because I had one move wrong early on that took a while to identify. Does anyone know how this happens? I'm running 64-bit Windows 7.</p>

<solitaire>
Why am I seeing the same 3 Spider Solitaire games today that I saw 2 days ago
Forget I was ever here
# Why am I seeing the same 3 Spider Solitaire games today that I saw 2 days ago

(Asked by: username_0 on 2015-06-29)

For the third time in 5 or 6 games today and yesterday I am seeing the same Spider Solitaire layout that I saw two days go. These three games all had very unique patterns, and took a large number of moves to solve, nearly 5,000 the second time on one because I had one move wrong early on that took a while to identify. Does anyone know how this happens? I'm running 64-bit Windows 7.

**Tags:** solitaire


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## 1 answers

### Answer by username_1 on 2015-06-29. Score: 1

The random number generator could have been seeded with the same seed, which would cause the same sequence of random number to be generated. The RNG in Microsoft's C library repeats every ~32,000 numbers (which is pretty abysmal), so there's effectively only that many seeds.

Different seeds:

```
>perl -E"say srand; say join ' ', map int(rand(52))+1, 1..10;"
1819759215  # The seed
41 35 23 9 35 2 41 11 50 51

>perl -E"say srand; say join ' ', map int(rand(52))+1, 1..10;"
994223390
47 13 12 51 35 7 37 42 11 2

```

But what if the same seed was picked the next day:

```
>perl -E"srand(994223390); say join ' ', map int(rand(52))+1, 1..10;"
47 13 12 51 35 7 37 42 11 2

```


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