A rudimentary tetris clone that fits into a 512b bootsector of x86 devices and works without an operating system
nasm utris.asm -o utris.o
# Either prepare a floppy disk image for an emulator:
dd if=/dev/zero of=floppy.img bs=1k count=1440
dd if=utris.o of=floppy.img conv=notrunc
# Or install on a physical floppy, HDD or a USB disk
# for booting a real device (USE WITH CAUTION):
dd if=utris.o of=/dev/disk2
move - left/right/down
rotate - up
drop - space bar