SPACE INVADERS handwritten flowchart 2

There are three types of the Invader laser beam, which are named RAY A, RAY B and RAY C. For Ray B and RAY C, the timing of appearance is preset, and this table determines that which Invader (each one is numbered in the array of the Invaders) fires RAY B / RAY C. Ray A, in the meantime, is fired from the invader closer to the player's laser cannon (SKETCH 6).