Waterfall generation type

The Waterfall generation is a newly added generation that is seen inside every normal server in Word Bomb. Waterfall is mostly considered to be a harder version of PrefAlt as it is harder since it occasionally spawns 3-letter prompts on the Black Bomb and Red Bomb. The prompt generator will grab a random prompt with 25 solutions or more within a certain difficulty range. Depending on the current bomb type, harder prompts may begin to appear. This generator will completely respect the bomb's preferred prompt length, meaning that no one-letter prompts will ever generate. However, on two-letter prompts, as the difficulty range starts to increase, the chances a three-letter prompt generates instead also increases.