I built a time machine. It's an idle game model. Here's how it works: First I get the date object and I transform it to make it into a variable I can manipulate. Then time is deduced every second and the machine goes back into the past. I transform the date into a number for internal calculation to make it easier. 2020.5674 is the year 2020 with 56.74% of it already passed, so somewhere in mid July. Then there is a database. That's the part with a lot of work. Basically, any historic event has some sort of duration. So depending where the player is, certain events will be displayed in organized lists. So with the 2020.5674 example, the lists would indicate you're in the middle of the COVID crisis, Donald Trump was president, the Yemeni Civil War was going on, the Big Bang Theory was still an active TV show etc... I have categories for pop culture, television, etc... As the player goes back in time, the lists get remade. The database is contained in an array and looks like this for each item: "The Eiffel Tower",4,1887.074,2050.999, So the first element is just the name of the item as it will appear. The second one is a tag that indicates what category it should belong to and the two other numbers are the date the thing existed, or the event was going on, expressed as a fraction for ease of calculation. I also made utilities along the way, such as a page that allows me to get that fractional number instantly by entering a date as input. So basically, a function itterates through all these items and if the category exists, it will be displayed with all the elements whose duration the present date is included in. (I found it easier to do it by concatenating a string than appending tons of children) Now I do have that concept officially copyrighted and I intend to redo it eventually, much bigger, with more details, allowing the user to click on items and get more info, etc... So I don't mind if you do something like that for your own use... just don't publish it under your name. Answer from Acceptable-Tomato392 on reddit.com