Computer Science Games

How a computer works, layer by layer

Almost nobody is taught what a computer is. They are taught what it does - run apps, hold photos, connect to things - which leaves the machine itself as magic. Computer science at its foundation is not magic and is not even especially complicated; it is a small number of ideas stacked on top of each other, and all of them can be handled directly.

The bottom of the stack is binary. A computer has no digits, only switches that are on or off, so every number it holds is built from place values that double: 1, 2, 4, 8, 16. Binary Blocks makes you assemble numbers that way until the pattern is obvious, which is also the moment 'a byte is eight bits' stops being a phrase and becomes a fact with a shape.

One level up are logic gates - circuits taking on-or-off inputs and producing one answer. Logic Gates puts a circuit board in front of you and introduces one gate at a time: flip the toggle switches, watch the current run along the copper tracks into a chip, and see whether the bulb lights. NOT, AND, OR and XOR, and the NAND and NOR you can build from them, are the complete vocabulary from which every processor on earth is assembled, and there is no step between them and a working CPU except quantity.

Pixel Painter covers the output side. A screen shows no pictures, only a grid of coloured squares, and every colour is three numbers saying how much red, green and blue light to mix. Mixing those yourself is where most people learn, with some surprise, that red and green light make yellow - because this is light being added, not paint being mixed.

The last two games are about algorithms, which is the study of how a job gets done and what that costs. Sort Sprint makes you the inner loop of a bubble sort so you feel every comparison, then shows what the same method would cost on a thousand items. Binary Hunt does the opposite: it shows how halving turns a thousand possibilities into ten guesses. Between them they teach the intuition behind efficiency long before anyone needs the notation for it.

Pathfinder takes that intuition onto a map. A sat-nav or a game character finds its way with a search algorithm, and here you watch three of them flood a night-time city: breadth-first search spreads out evenly and always finds the shortest route, depth-first search dives down one street and often takes the long way, and A* uses a guess of the distance left to head straight for the goal. Every number on screen comes from running the real algorithm on that map.

Morse Code goes back to where digital communication began. Every letter is a pattern of two signals, and the most common letters were given the shortest patterns on purpose - E is a single dot - which is the same trick modern compression uses to shrink a file. Tapping it out on a telegraph key makes the idea of encoding information physical.