28 · simulations
The Lab
Every simulation on Code Quest in one place. Experiment freely: you can't break anything, and nothing needs fixing afterwards.
Bits and data5
💡
Switches and lampsFour switches, four lamps. Turn them on and off and discover how a computer builds every number out of ON and OFF.Open 🔢Challenge
Binary challengeMake the target number with eight switches worth 128, 64, 32, 16, 8, 4, 2 and 1. How many can you solve?Open 🖼️
Pixel painterPaint an 8 × 8 picture and read the eight numbers a computer stores for it. Every image on your screen works this way.Open 🔤
Letters are numbersType any word, in any alphabet, and see the number and the bits behind each character, emoji included.Open 🎯
Why 0.1 + 0.2 ≠ 0.3Flip the 32 bits of a decimal number: sign, exponent and fraction. See exactly what is stored, and the error left over.Open Logic and circuits6
🚦
Logic gatesAND, OR, NOT, XOR, NAND and NOR: flip the inputs, watch the lamp and read the truth table as it lights up.Open ❓Challenge
The mystery gateA gate is hidden in a box. Test it with the four input combinations and work out which one it is.Open ➕
A circuit that addsFive logic gates add three bits. Follow the signals through the two XORs, two ANDs and one OR of a full adder.Open 🧮
The 4-bit adderFour adders in a chain, passing carries to the left. Set two numbers and make it overflow.Open 🧷
A circuit that remembersTwo gates feeding each other hold one bit after you let go of the button. This loop is the seed of all computer memory.Open 🗄️
An 8-bit registerEight latches store one byte. Set the data wires, send a clock pulse and watch the register capture them.Open Transistors and chips3
⚛️3D
Inside a transistorA transistor sliced open in 3D. Raise the gate voltage and watch electrons gather under the oxide and open a channel.Open 🔧
Gates from transistorsBuild NOT with two transistors, NAND and NOR with four. See which switches conduct and which path wins.Open 📈
Moore's lawFrom 2 300 transistors in 1971 to more than 100 billion today: slide through fifty years of chips on one chart.Open Inside the processor4
🧠
A tiny computerA complete 8-bit computer with 16 bytes of memory. Step through fetch, decode and execute one clock tick at a time.Open 🔁
Jumps make loopsThe same tiny computer running a countdown. Watch one JUMP instruction turn a straight list into a loop.Open ✖️
Multiplying without ×This processor can only add and subtract. See how a loop of additions multiplies two numbers anyway.Open 🪜
From code to electronsFollow one line of Python down seven layers: assembly, machine code, gates, transistors and finally voltages.Open Programs and languages4
🤖Challenge
Program the robotWrite the exact steps that take the robot to its battery. It will do precisely what you say, even when you are wrong.Open 🔂Challenge
Robot loopsToo few command slots to reach the battery? Find the pattern, write it once and repeat it.Open 👣
Run code line by lineStep through decisions, loops, functions and recursion. Watch each variable change and the call stack grow and shrink.Open 🏭
A compiler in four stepsType a calculation and watch it become tokens, a tree, machine instructions and finally an answer.Open Algorithms2
Theory of computation2
History of computing2
🕳️
Punch a cardType a line and see it punched into an IBM card, hole by hole. For decades, this was how every program was written.Open ⏳
180 years of codingThe same small job, programmed in eight eras: Lovelace's cards, ENIAC's cables, machine code, assembly, FORTRAN, C, Python and a sentence to an AI.Open