Letter H pattern lock
How to draw the letter H 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 H on a 3×3 grid
An exact letter H 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 4–7.
- Start at dot 1 (top-left corner).
- Go to dot 4 (middle left).
- Go to dot 5 (center).
- Go to dot 6 (middle right).
- Go to dot 3 (top-right corner).
- Finish at dot 9 (bottom-right corner), passing over dot 6 again.
PatternGuard’s analyzer gives it 12/100 (Very weak): 6 dots, 1 crossing, starting at the top-left corner.
On 3×3 this is exactly the same pattern as the number 4: anyone who guesses one has guessed the other.
Is a letter H 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 H, this is one of the first patterns someone who knows you would draw.
A stronger way to use the letter H
If you like the letter H, don’t draw it on its own. Adding 1 dot before it and 1 after it keeps the shape you remember but hides it inside a longer stroke: 8 → 1 → 4 → 5 → 6 → 3 → 9 → 2 scores 53/100 (Moderate), against 12 for the plain letter H.
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 H 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 H 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 9–13.
Order: 1 → 5 → 9 → 10 → 11 → 12 → 16 → 8 → 4
PatternGuard’s analyzer gives it 19/100 (Very weak): 9 dots, 1 crossing, starting at the top-left corner.
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.