The trails are the effect
Take away the fading tail behind each column and it stops working entirely. It’s just characters moving down a screen. The whole thing lives in the fade, and specifically in the fact that the leading character is brighter than everything behind it, which is what makes your eye track downward instead of side to side.
Columns run at different speeds. If they all fell at the same rate you’d see rows, and rows are the enemy here.
Depth is the version worth seeing
Switch it on and the columns get sorted into three planes. Near ones are big, bright and fast. Far ones are small, dim and slow. Nothing about the code changes, just the scale, and suddenly the flat screen has a Z axis. It’s the cheapest trick in the file and the best one.
Type into it
The prompt at the bottom accepts anything. Whatever you type gets pulled into the rain and scattered through the columns, so your own words come falling back at you a few seconds later, broken up and mixed with everything else. Type your name. It’s a bit unnerving.
Colour
Green is the default and green is correct. The other options exist because people asked: amber, which reads as an old terminal rather than anything cinematic, and a cold blue that looks like a system error. Both are worse. Try them anyway.
Heavier and faster
Density doubles the number of columns, which will make a laptop fan spin up. Speed makes the whole thing hard to read, which is arguably more accurate. Running both at once on the deepest setting is a lot, and after about thirty seconds you’ll turn one of them off.
Related dark screens
Google terminal is the one where you actually type commands rather than just watching text fall. Google batman is the other night-time page and uses a searchlight instead of rain. Google black hole is the darkest thing here by some distance.
For falling things that aren’t ominous, google snow. Everything is indexed on google easter eggs.
