Workshop › Conway's Game of Life › Step 3 of 32

One living cell

What we are doing

A live cell is a small green square. We draw one at column 3, row 2, one pixel smaller than the cell so a thin gap separates neighbours.

```js
ctx.fillStyle = '#4ade80'
ctx.fillRect(3 * CELL, TOP + 2 * CELL, CELL - 1, CELL - 1)
```

What it means

• 3 * CELL is 24: column 3 starts 24 pixels from the left.
• TOP + 2 * CELL is 52: row 2 starts 2 cells below the top of the grid, which itself starts at TOP.
• CELL - 1 (7) is the size of the square, leaving a 1-pixel gap.

Your turn

At the very end, leave an empty line and write the two green lines. Press Run.

Skills: Drawing on a canvas

← Measure the grid A function that draws →

All steps

1. The board
2. Measure the grid
3. One living cell
4. A function that draws
5. The world in memory
6. Draw every living cell
7. A random soup
8. Count the neighbours
9. Four rules
10. Draw again and again
11. Next generation with N
12. Count the generations
13. Show the generation
14. A world without edges
15. Count the living
16. A generation every few frames
17. Let it live
18. Running or not
19. One place for the buttons
20. Space to play, N to step
21. Clear and shuffle
22. Where is the pointer?
23. Which cell?
24. Click a cell
25. Paint or erase?
26. Drag to paint
27. Patterns from text
28. The glider gun
29. Fire the gun
30. Buttons on the screen
31. Tap the buttons
32. Build it yourself: a world at rest