Examples of well presented questions

Sometimes a question is underspecified or ambiguous. Other times a question is fully specified but very long and dry to read. In between there are questions which seem perfect - all the information is there but it's also a joy to read, and makes you want to start thinking about possible answers right away.

Answer with a link to an example question (your own or someone else's) and optionally a brief explanation of why it makes a good example. Then votes will bring the very best to the top, and this meta post can be linked to for examples of how to improve a question when someone posts something too brief or too deep.

This is always going to be subjective so I thought a list of examples might be more useful than trying to define precisely what makes a well presented question. Although there may be overlap, this won't be the same order as the votes the questions have on main, as voting there is also on the subject matter and the challenge itself, not just on how it is presented.

Morse the New Year

• Clear specification
• Not too long
• It contains an example output
• I'm flattered. ;) One shortcoming of my challenge is an unambiguous spec for the sound levels, which is slightly problematic with submissions using instruments. Exhibit A. – Martin Ender Jan 4 '15 at 10:49

Calculate practical numbers

Pro:

• The definition of the problem is solid and understandable.
• Contains relevant references to Wikipedia and OEIS.
• Contains a very clear example.
• It clearly specifies the admissible formats of answers ("program, function or verb").
• Contains a sufficient number of test cases, including important cases like 1 and 250000.
• In summary: It's a concise but complete spec for a not-so-trivial challenge.

Con:

• Only a very minor detail, but for programs it could be specified whether input should be via STDIN, command-line argument or prompt. (We've got defaults for this now, but we didn't at the time.)

Construct a graph

I think most, if not all, of Zgarb's challenges are exceptionally well presented (and most of them follow the same format):

• Clear description of the challenge's background, along with all necessary definitions.
• Clear input/output specification.
• Very importantly, a good set of test cases which covers all relevant edge cases.

Nested Boxes

I could have picked a few of Joey's but I think this is the best example. It has:

• An interesting problem
• A clear and detailed specification leaving little room for ambiguities
• A number of sample inputs and outputs for testing while developing an answer
• A test script for making sure the answer fully meets the specification and handles any corner cases.