You've seen how a handful of switches becomes a number, and how numbers get added, subtracted, multiplied, and divided using nothing but logic gates. Now: how does a number turn into the picture on your screen?
Eight bits, wired together, are called a byte. Click any switch below to flip it between 0 and 1 — same switches as Chapter 1, just eight of them in a row.
Computers often use that exact number to answer one question: how bright should this pixel be? 0 means fully dark, 255 means fully bright.
A screen pixel is usually made of three tiny lights: red, green, and blue. One byte controls how bright each one burns. Mix all three, and you get any color your screen can display.
A photo, an icon, this very webpage — all of it is millions of pixels, each one just three bytes of red/green/blue, sitting one after another in memory. Try it: pick a color and paint the grid below, pixel by pixel.
Your screen doesn't have 64 pixels — it has millions. And it doesn't redraw once — it redraws the whole thing about 60 times every second, to make motion look smooth.
That's over 100 million pixel updates every second. One processor, working through them one at a time — the way you just painted that grid above, cell by cell — would be far too slow. That's the exact problem a different kind of chip was built to solve.