ZX81 tetris

This is a free remake of tetris for the computer which many describe as igniting the British computer industry, the legendary Sinclair zx81. Originally was attempting to write this to run on an unexpanded zx81 with 1k of memory but it proved to difficult and so now here it requires 16k. Also there are "no frills" its the basic tetris game wirh no intro screen. But it plays well like real tetris.