Playfield: a well conventionally 10 cells wide and 20 or more visible rows tall.; Seven tetrominoes: I, O, T, S, Z, J and L, each four cells.; Controls: move left and right, soft drop, hard drop, rotate clockwise and anticlockwise, and hold.
Why people argue about this
People often assume that the playfield must be exactly 10 cells wide by 20 rows tall, forgetting that it can vary within certain parameters as long as it's "conventionally" sized. The confusion arises because they overlook the flexibility in dimensions while focusing on the specific cell count and row height.
