yeah, it's clearly not a 10-liner -- the code is an optical illusion.
Now, the question bothering me: is a true 10 line tetris possible?
Ummm…. Probably?
Pieces could be defined by
“SRU\” — Start, move Right, move Up, move diagional down and right. Produces this piece:
@
@@@
Other 4 command combos could define the rest of the pieces in a similar manner. Just put them all in a single string to store them and manage them with MID$. <—- All in 1 line of code.
Then it’s a DO…
IF _KEYDOWN = (left arrow) then move to next entry in MID$ list MOD 4 to rotate ELSEIF key down…. ELSEIF key right….. <— All in 1 line of code.
check screen to see if characters below are filled…. YES, place on top, check for full blocks NO… Move down
LOOP until no place to place block at top
5 lines for the base core (screen 0 to track pieces), so that gives a little wiggle room to try and do a minimalistic version in 10 lines.