Numbers, letters and patterns that hide the answer.
A Message from a Friend★☆☆about 4 min
The Notice to the Bird Park★☆☆about 3 min
The Safe Cipher Is a String of Numbers★☆☆about 3 min
The Safe Code Is a Sequence of Numbers★☆☆about 3 min
The Postmark on the Warning★☆☆about 3 min
Two Wills★★☆about 4 min
The Clue of “S”★★☆about 5 min
The Number She Left★☆☆about 5 min