Height-map low resolution displacement
Landscape topography from grayscale image
What is a "static" function in C? The question was about plain  functions, not  static methods, as clarified in comments.  I understand what a static variable is, but what is a static function?  And why is it that if I declare a function, let's say void print_matrix, in let's say a.c (WITHOUT a.h) and include "a.c" -  I get "print_matrix@@....) already defined in a.obj", BUT if I declare it as static void print_matrix then it compiles?  UPDATE Just to clear things up - I know that including .c is bad, as many of you pointed out. I just do it to temporarily clear space in main.c until I have a better idea of how to group all those functions into proper .h and .c files. Just a temporary, quick solution. Rich Snippets not working (and working at the same time?) It seems that I'm missing something about this.  First of all, the series is convergent: $\lim_{n\rightarrow\infty}\frac{2^{-n-1} (n+1)^2}{2^{-n} n^2}=\frac{1}{2}$ (ratio test)  What I tried to do is to find a limit of a partial sum $\lim_{n\rightarrow\infty}S_n$ as follows: $S_n=\frac{\frac{1}{6} n (n+1) (2 n+1)}{\frac{1-\left(\frac{1}{2}\right)^n}{2 \left(1-\frac{1}{2}\right)}}$. Still, the limit is $\infty$ and I'm clearly doing something wrong. Addressing a former office-holder by that office's title When is it appropriate to use an "expired" honorific to address or refer to a person?   In the U.S., former state governors are occasionally referred to as "Governor So-and-so", although they have not held that office for several years. I see this happening most often when the former governor is actively campaigning for a new office (usually U.S. President), and my impression is that it's done only by someone with an interest in the campaign (for or against) rather than a (relatively) neutral party like a newspaper.  Certainly this could be used as a jab: in a political campaign for high office, addressing one's opponent by a former title — lower than one's own — could imply that the opponent is not qualified for the new job. It could also be used the other way around, to remind listeners that a candidate one supports used to hold an important title.  I'm curious whether there are formal rules for this in the U.S., or at least style or journalist guidelines, for various offices. Are ambassadors, for example, entitled to some sort of emeritus honorific? In a topological space, why the intersection only has to be finite? I was wondering if there is a reason why in the definition of a topologic space, the reunion of any collection of open sets is also an open set but the intersection has to be finite to be a set.  Is there because of the definition of an open set itself ? I have always seen it as a definition, but now I want to know why.  Thanks for your help. What's the correct way to do division using a backslash? If I write $a/bc + d$, will that be equal to $(a/(bc))+d$?   Basically, if I place a slash, will I divide by what's directly behind the slash $(b)$, the term that's behind the slash $(bc)$, or everything after the slash $(bc+d)$? Reputation misaligned in new topbar In the sites dropdown, the reputation scores are misaligned:    This seems to happen only on Firefox (56.0), both on macOS (10.13) and Windows (7, 10) (thanks @Tom and @MonicaCellio). I've tested a couple of other browsers which do not have this problem. I've already cleared my cache. Is it a weakness to use a single shared secret for protecting messages using a Encrypt-then-MAC scheme?    Assuming a system is using AES-256-CBC and a SHA1-HMAC and the same secret key for both operations.  Upon intercepting one of these messages and attacker could brute force this secret key by trying to solve the HMAC or by successfully decrypting the first block of the ciphertext.  Performing  a decryption on a single block of AES-256 should be a lighter operation than performing a SHA1-HMAC on a potentially large message.  Therefore AES-256 is ideal for a massively parallel brute-force attack and the use of the SHA1-HMAC doesn't hurt the system.  Is this approach sound, or is there an attack that has not been taken into consideration? How does the Girl-Genius web-comic relate to the Agatha H. books? After spending some time reading  I was convinced to buy the book.  I've ordered what I think is the  in my local bookstore (yay local) and it seems to relate to the first one or two years of of web content, but I can't be sure.  My question is: "how does the book series line up with the Web comic?"  Does it contain specific episodes/adventures, relate to strips from a specific time-span or is it simply an assortment of episodes?  UPDATE: They are amazing.  It is interplanetary war in the introduction!!!!  Yes! On the Goblet of Fire Barty Crouch exactly got Mad-Eye's voice when he transformed into him, but on the Deathly Hallows, they were all able to have their own voices instead of Harry's. Why is the effect of the polyjuice potion inconsistent? What punctuation should follow after a list introduced by a colon? The whole department: John, Jeff, Jean, and the accountant [?] were thrown into jail. Ability to view your own questions The app doesn't have a way to show your own questions. It would be nice to get a quick handle to those. What does a de Broglie wave look like? What does a  wave look like? Are de Broglie waves transverse or longitudinal?   Can they be polarized?    What about the de Broglie wave of a ground state neutral spin-zero Helium 4 atom?   What experimental evidence do we have that supports the detailed nature of a de Broglie wave?     I have always assumed that de Broglie waves were mathematically  identical to electromagnetic waves, but I just realized there is no basis for this assumption, and in fact it must be false, unless there is an analogue to both the magnetic and the electric components of the electromagnetic wave.  So what does a de Broglie wave "look like"? How do I check if an object has a specific property in JavaScript? This is fairly easy.  If I go to https://webserver.com/someurl?a=b, will the someurl?a=b part be protected, or just the contents of the site? Is the following sentence correct English?      Have you the address?   The address in question is obvious to the person being asked.  It's normal to ask such a question as "Do you have the address?" or even "Have you got the address?" But is it acceptable to use just the verb have without do or got? Why does everyone's wand still work for them? How to find application's path from command line? For example, I have git installed on my system. But I don't remember where I installed it, so which command is fit to find this out? If, one fine day, someone found a contradiction in ZFC (or even ZF), what implications would such an event have for mathematicians? Is there currently any backup axiomatic system on par with ZFC that would enable mathematicians to continue pursuing mathematics, should the unthinkable occur? Splitting a string into words and punctuation