surely its just programming valves lined along the top to release water in a given pattern (in a way the waterfall has a resolution - the number of valves along the top x the time taken for the water droplets to fall to earth down the side), as long as the jets all fire water at the same rate then it'll work, then the patterns need to be programmed into the computer that controls them so it opens and closes specific valves at the required time. i presume the valves would have to release water at a rate that would match the speed at which the water droplets fall to earth or the pattern would start to disintegrate as the droplets speed up
dont mean to make it sound simple as its quite obviously not, but the actually fundementals behind it are quite easy.