40 Lines?

[Blitz]

Why is it exactly 40 lines

[StS]

Because 100 pieces?

[FelipeMayrink]

And 10 tetrises?
And the game kinda likes the number 4.

[morningpee]

I think The New Tetris (1999) was the first game to have a speed-based single player mode, originally known as Ultra.  In this mode, the player has to clear 150 lines, though a large bonus is given for square platforming, reducing the minimal lines necessary to complete the mode to 8 lines.  Sprint used to be a time-based mode, the goal being to clear as many lines as possible within 3 minutes.

Later, TGM Ace's "Tetris" mode (2005) added a mode where you actually have to clear 150 lines.

Lockjaw (2006) includes a 40 lines mode.  On that note, Jono recently got 25.11 seconds, that beast.

I could be wrong, but I think the first official game to have a 40 lines "sprint" mode is Tetris Zone (2007).

Why is it exactly 40 lines

Because of Tepples/Damian Yerrick.

Edit: As caffeine points out, Tetris DX has a 40 lines mode.  It also precedes all games I just mentioned.

[caffeine]

The earliest game with a formal 40 lines I can think of off the top of my head is Tetris DX. (Before that, B-Type of 25 lines was standard.) I like the 10 Tetrises theory. Most nooblets can finish it within a reasonable amount of time. 10 lines would be too little, and 100 would take new players way too long.

This would be a good question Henk Rogers & co.