Letter O pattern lock
How to draw the letter O as an Android unlock pattern, step by step, on the standard 3×3 grid and on 4×4, with the security score PatternGuard’s analyzer gives each version.
The letter O on a 3×3 grid
An exact letter O isn’t possible on the 3×3 grid: Android never lets you select a dot twice, and this shape would need it. The closest pattern leaves out the line 1–4.
- Start at dot 1 (top-left corner).
- Go to dot 2 (top middle).
- Go to dot 3 (top-right corner).
- Go to dot 6 (middle right).
- Go to dot 9 (bottom-right corner).
- Go to dot 8 (bottom middle).
- Go to dot 7 (bottom-left corner).
- Finish at dot 4 (middle left).
PatternGuard’s analyzer gives it 14/100 (Very weak): 8 dots, 0 crossings, starting at the top-left corner.
On 3×3 this is exactly the same pattern as the number 0: anyone who guesses one has guessed the other.
Is a letter O pattern safe?
Not really. Letters are among the first shapes anyone tries: research on real-world patterns found that about 1 in 10 is shaped like a letter, often the initial of a partner or a child (Løge, 2015). If your name or your partner’s name starts with O, this is one of the first patterns someone who knows you would draw.
A stronger way to use the letter O
If you like the letter O, don’t draw it on its own. Adding 1 dot before it keeps the shape you remember but hides it inside a longer stroke: 5 → 1 → 2 → 3 → 6 → 9 → 8 → 7 → 4 scores 36/100 (Weak), against 14 for the plain letter O.
It’s still published here, so treat it as an example of the idea, not as a pattern to copy. The safest pattern is one of your own that doesn’t spell anything.
The letter O on a 4×4 grid
Stock Android uses the 3×3 grid; 4×4 shows up in some custom ROMs and lock-screen apps, and the simulator supports it. An exact letter O isn’t possible on the 4×4 grid: Android never lets you select a dot twice, and this shape would need it. The closest pattern leaves out the line 2–5.
Order: 2 → 3 → 8 → 12 → 15 → 14 → 9 → 5
PatternGuard’s analyzer gives it 40/100 (Weak): 8 dots, 0 crossings, starting at the row 1, column 2. On 4×4 it’s the same pattern as the number 0.
Why some letters can’t be drawn exactly
Android’s pattern lock has three rules: at least 4 dots, no dot can be selected twice, and if the stroke passes over a dot you haven’t used yet, Android adds it automatically. Passing over a dot you already used is allowed, which is how letters like P, R or F can be traced exactly. On 3×3, shapes with a closed loop or three or more loose ends (like A, B or O) still need one line left out or one line added; the 4×4 grid has more room, but not always enough.