Letter C pattern lock
How to draw the letter C 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 C on a 3×3 grid
The letter C can be drawn exactly on the 3×3 grid in a single stroke, without going back over any line.
- Start at dot 3 (top-right corner).
- Go to dot 2 (top middle).
- Go to dot 1 (top-left corner).
- Go to dot 4 (middle left).
- Go to dot 7 (bottom-left corner).
- Go to dot 8 (bottom middle).
- Finish at dot 9 (bottom-right corner).
PatternGuard’s analyzer gives it 9/100 (Very weak): 7 dots, 0 crossings, starting at the top-right corner.
Is a letter C 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 C, this is one of the first patterns someone who knows you would draw.
A stronger way to use the letter C
If you like the letter C, 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: 5 → 3 → 2 → 1 → 4 → 7 → 8 → 9 → 6 scores 36/100 (Weak), against 9 for the plain letter C.
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 C 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. The letter C can be drawn exactly on the 4×4 grid in a single stroke, without going back over any line.
Order: 16 → 15 → 14 → 9 → 5 → 2 → 3 → 4
PatternGuard’s analyzer gives it 17/100 (Very weak): 8 dots, 0 crossings, starting at the bottom-right 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.