Google Matrix
Watching the columns
Each column falls at its own pace with a bright character at the front and a tail that dims behind it. Nothing loops in step, so the screen never settles into a pattern you can predict, which is most of why people leave it running in a spare tab.
Lengthen the trails and the whole thing turns into rain rather than dots. Invert it and you get the version everyone pictures: pale characters on black.
The glyphs
Digits, katakana, and the six letters of the logo mixed in. The word surfaces on its own every few seconds, usually in pieces, occasionally whole. The film used mirrored katakana, which is why the shapes look almost readable and never quite are.
Where it stands
Falling code has been a coding exercise since 1999 and turned into a search page takeover once browsers could draw fast enough. There has never been an official version, so google matrix, matrix google and google matrix 3d all point at rebuilds. The 3D ones just add perspective to the same columns.
The other page that throws the layout away entirely is google terminal, which keeps the plain text but lets you type back.
Anything else that takes over the whole frame?
The night sky in google batman, where you aim the light yourself.
Will it slow my machine down?
Long trails and dense columns together will make an older laptop work. Drop one of the two and it settles.