Minute Long Redstone Delay
How to delay or slowly loop commands?
For example, rigid bodies and fluid. I know it's kind of possible by setting the rigid bodies as fluid obstacles, but it's not "true" interaction in that the fluid does not affect the rigid bodies...  By "true" interaction I mean where two (or more) physics systems affect each other simultaneously. For example, with rigid body and cloth, the rigid body affects the cloth but the cloth doesn't affect the rigid body (at least the way I'm doing it), so the rigid body just eventually stretches the cloth to an extreme and falls through...  Are there any ways to achieve this? (for any interaction, not just rigid bodies and fluid)  Or, if not, does anyone know whether there are any plans to implement this sort of feature?  Thanks I updated MacOS Sierra's Apache and PHP, and now whenever I $ sudo apachectl restart I get this:  AH00557: httpd: apr_sockaddr_info_get() failed for My-MacBook-Pro.local AH00558: httpd: Could not reliably determine the server's fully qualified domain name, using 127.0.0.1. Set the 'ServerName' directive globally to suppress this message   Things I've tried so far that didn't work:   Setting ServerName localhost in /etc/httpd.conf Setting ServerName localhost:80 in /etc/httpd.conf Setting ServerName 127.0.0.1 in /etc/httpd.conf Setting ServerName 127.0.0.1:80 in /etc/httpd.conf Ensuring 127.0.0.1       localhost is set in /etc/hosts Repeatedly restarting Apache Why don't electromagnetic waves require a medium? Show that unit circle is not homeomorphic to the real line I need to evaluate the limit without using l'Hopital's rule.  $$\lim_{x \to 0}{\frac{\sqrt{1+x\sin{x}}-\sqrt{\cos{2x}}}{\tan^{2}{\frac{x}{2}}}}$$ Simple approximation of Inverse Incomplete gamma function I've got a list of Python objects that I'd like to sort by an attribute of the objects themselves.  The list looks like:  &gt;&gt;&gt; ut [&lt;Tag: 128&gt;, &lt;Tag: 2008&gt;, &lt;Tag: &lt;&gt;, &lt;Tag: actionscript&gt;, &lt;Tag: addresses&gt;,  &lt;Tag: aes&gt;, &lt;Tag: ajax&gt; ...]   Each object has a count:  &gt;&gt;&gt; ut[1].count 1L   I need to sort the list by number of counts descending.  I've seen several methods for this, but I'm looking for best practice in Python. Writing conditional (if/then) statements into ArcGIS Field Calculator using Python Parser? I have gotten stuck on seemingly simple ArcGIS field calculator python expression.  I obtained a great answer to a another similar question a few years ago: . Now I need to populate a new field based on 6 ranges of values (bedrock depth).  My attempt at writing this expression is below:    I just need to populate the empty field "bedrockdp" using the ranges in the toc called brockdepmin.     Pre-Logic Script Code:  def !GRIDCODE! (value):     if value &gt;0 and value &lt; 50:         return "0 - 50 cm from the surface"     else:         return "n/a"   bedrockdep =  GRIDCODE (!bedrockdep!) Four complex numbers $z_1,z_2,z_3,z_4$ lie on a generalized circle if and only if they have a real cross ratio $[z_1,z_2,z_3,z_4]\in\mathbb{R}$ Let $[z_1,z_2,z_3,z_4]$ denote the  of the complex numbers $z_1,z_2,z_3,z_4\in \mathbb{C}$. Show that the distinct points $z_1,z_2,z_3,z_4\in\widehat{\mathbb{C}}$ lie on a generalized circle if and only if $[z_1,z_2,z_3,z_4]\in\mathbb{R}$.    I saw this statement claimed in , and wondered how one would go about showing it. I know of some facts we could work with:   First, the definition: A  in $\mathbb{C}$ is either a circle or a line in $\mathbb{C}$. I know that a Mobius transformation maps generalized circles to generalized circles. I know that if $f$ is a Mobius transformation and $z_j'=f(z_j)$, $j=1,2,3,4$, then $[z_1',z_2',z_3',z_4']=[z_1,z_2,z_3,z_4]$.   I have posted a potential proof as an answer below. Please let me know if you think it's complete. Thank you! How to run Wireshark on Ubuntu 17.10 I used to run wireshark on ubuntu 17.04 with  ~/$ sudo wireshark   but now (just after update to 17.10) when I write the same I get an error  ~/$ sudo wireshark      QStandardPaths: XDG_RUNTIME_DIR not set, defaulting to '/tmp/runtime-root'     Invalid MIT-MAGIC-COOKIE-1 keyQXcbConnection: Could not connect to display :0 Problem:Let $k$ be an odd positive integer. Prove that $(1+2+3...+n)|(1^k+2^k+3^k+...+n^k)$ for all positive integers $n$.  My Attempt: Proof (By Induction on $k$): Let $P(k)$ be the proposition that $(1+2+3...+n)|(1^k+2^k+3^k+...+n^k)$ for all positive integers $n$ when $k$ is odd. Then $P(1)$ and $P(3)$ are trivially true. So for $k\geq 5$, we assume that $P(k)$ holds. We would like to show that $P(k+2)$ also holds. In order to do that consider the following sums  $$1^{2}(1^k+2^k+3^k+...+n^k)=1^{k+2}+2^k+3^k+...+n^k$$ $$2^{2}(1^k+2^k+3^k+...+n^k)=2^2*1^k+2^{k+2}+2^2*3^k+...+2^2*n^k$$ $$..$$ $$n^2(1^k+2^k+3^k+...+n^k)=n^2*1^k+n^2*2^k+n^2*3^k+...+n^{k+2}$$ Note that $$1^2(1^k+2^k+3^k+...+n^k)+2^2(1^k+2^k+3^k+...+n^k)+...+n^2(1^k+2^k+3^k+...+n^k)\equiv 0\pmod {\frac{n(n+1)}{2}}$$  Therefore, if we denote $\sum_{i=1}^{n}i^2=s$, then    $(t)(1^k+2^k+3^k+...+n^k)-t+\sum_{i=1}^{n}i^{k+2}\equiv 0\pmod {\frac{n(n+1)}{2}}$ which implies that $P(k+2)$ holds. Hence by PMI we are done.  Now I am a bit hesitant in convincing myself whether this proof is correct or not. This is because I have never seen induction performed in this manner. Any reasons as to why this argument falls would be much appreciated. After upgrading to Windows 8, hard disk sporadically does not work; what's wrong? I dont know whether I can ask this question here or not. Please consider this if it not a proper place.  Here is my problem, I was using Windows XP previously and I changed it with Windows 8. After installation of Windows 8 when I booted it up, I found my HDD behavior changed. Sometimes it is running and sometimes it is not.  My system specification is :  Intel Motherboard (945 Express Chipset) Processor (Core 2 duo) RAM (2 GB) HDD(500 GB)   When I open my HDD for getting the cause of problem (I open that casing and check head  and disk). I did not find any hardware visible problem. Just it is stop rotating, before it can boot OS.  Can someone help me to fix this problem or recover data in this case.  NOTE : Warranty period expired, and I have my 5 projects in that and some important documents. How to retrieve a module's path? I want to detect whether module has changed. Now, using inotify is simple, you just need to know the directory you want to get notifications from.  How do I retrieve a module's path in python? Assuming this is on the way, but having not seen it previously reported: I can't view myself from the sidebar, or anyone else by tapping them. View Self From Sidebar:   View Asker/Answerer:   View Commenter: What's the point in adding a new line to the end of a file? Some compilers (especially C or C++ ones) give you warnings about:  No new line at end of file   I thought this would be a C-programmers-only problem, but github displays a message in the commit view:  \ No newline at end of file   for a PHP file.  I understand the preprocessor thing explained in , but what has this to do with PHP? Is it the same include() thing or is it related to the \r\n vs \n topic?   What is the point in having a new line at the end of a file? Google Search Console domain property not in the list of properties I can add to Google Analytics Is it ethical to use a recommendation letter from a deceased professor? She was a really nice professor and she wrote me a good recommendation letter that resulted in a lot of good results with applications. Recently, this professor died from brain cancer, which was a fast and shocking death for me.  Tomorrow is the deadline for a grant. What should I do? Is it professional to use letters from the deceased? If $a, b, c >0$ prove that $ [(1+a)(1+b)(1+c)]^7 > 7^7a^4b^4c^4 $. I solved it using AM, GM inequalities and reached to $[(1+a)(1+b)(1+c)]^7 &gt; 2^{21}(abc)^\frac72 $ please help how to get $7^7(abc)^4$ in the inequality. Can older cards that refer to a player/opponent ever be used on planeswalkers? Why don’t photons interact with the Higgs field and hence remain massless?