Computers are deterministic machines. This means that if you give them the same input, and perform the same operations, you'll get the same output every time. With respect to the desk example, everyone gets the same pieces, follows the same instructions, and so builds the same desk.
Again, using the context of games, if everyone gets the same assets and algorithms to put them together, we will all get the same game and experience. Sometimes, this is the goal. However, in our case, we want to create game systems that are unpredictable and dynamic. Therefore, we need to introduce an element of randomness to procedural generation.
Pseudorandom number generation
Random number generation is simply the process of picking a number ...