I started working as a programmer in 2011 at a company located in ZiZhu Scientific Park, Shanghai. To memorize this event I opened this web site and name it "ZiZhuJY". "JY" means I want to make some noise to this world through this web site platform.
I had been teaching myself mathematics, so I made several online math tools. For example, "Online Function Grapher", "Plotter/Online statistical calculator", "Online Geek Calculator", "Online Matrix Calculator", etc. I can't live without them, especially in my studying math time. Why did I create them by myself? Because 1. I am a programmer so I have the ability to create them. 2. None of the tools made by other people/company can meet my requirements or fit my habit of using them.
For instance, several years ago I couldn't find a free online tool that can draw implicit functions quickly, so the "Online Function Grapher" was created. And another example, I can not find a calculator that supports multi-line expressions inputting, has the ability of displaying fractions and converting decimals to fractions quickly (I was stuned by this fact), so the "Geek Calculator" was created.