(This is denoted as max_n_ in the function below.)
Only 10,000 numbers can be drawn at once from. It is important to note that there were two challenges that I encountered when using drawing truly random numbers. (If you are concerned that I have lost the faith, please note that I am aware of the awesomeness of ggplot2 and its ability to create heat maps.) To create the bitmaps, I used the pixmap package rather than the much-loved ggplot2 package, simply because of how easy it was for me to create the plots. I have provided the function rand_bit_matrix, which requires the number of rows and columns to display in the plotted bitmap. Until today, I had only heard of the random package but had never used it. Also, for comparison, I chose to use the random package, from Dirk Eddelbuettel, to draw truly random numbers from. So, created equivalent plots in R to see if a rand equivalent would exhibit a systematic pattern like in PHP, even if less severe. But I was curious to see what would happen. Now, I would never use PHP for any (serious) statistical analysis, partly due to my fondness for R, nor do I doubt the practicality of the RNG in R. Cook’s discussion on testing a random number generator. 
For a good introduction to RNG, I recommend John D.
Random org generator#
However, it is silly that PHP’s random number generator (RNG) displays such an obvious pattern nowadays because there are several decent, well-studied pseudo-RNG algorithms available as well as numerous tests for randomness. Of course, the findings should not be too surprising, as there is a large body of literature on the subtleties, philosophies, and implications of the pseudo aspect of the most common approaches to random number generation. The post’s results suggest that pseudo-randomness in PHP is faulty and, in general, should not be underestimated in practice. Earlier, I found an interesting post from Bo Allen on pseudo-random vs random numbers, where the author uses a simple bitmap ( heat map) to show that the rand function in PHP has a systematic pattern and compares these to truly random numbers obtained from.
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