The phrase "a riddle for" is correct and usable in written English.
You can use it when introducing a riddle or puzzle that you want someone to solve or think about.
Example: "Here’s a riddle for you: What has keys but can't open locks?"
Alternatives: "a puzzle for" or "a conundrum for".
With this in mind, I have a riddle for you.
For another, laying down a bunt remains a mystery wrapped in a riddle for the Mets.
Could it be we unconsciously left a riddle for our future selves, all those years back, just to shake things up a bit?
He has described his process as "Hand Eye Chicken," and the poster above captures his ability to combine familiar but unconnected images in a way that seems as if he has solved a riddle for you.
THE question most asked of fashion reporters at this time of year is a riddle for the ages: What, oh what, to wear on New Year's Eve? My stock response, intentionally vague, has always been "sparkle".
Understanding Mr. Dylan is still a riddle for most, but Mr. Marcus seems to be so familiar with him that Mr. Dylan must wonder how he ever let someone who came to visit stay so long.
Again we hear the words, which now seem as nonsensical as a riddle meant for children: "There are known knowns.
Longstreth's detail and his variation are no longer a riddle built for one; "Bitte Orca" turns all that technique and compositional brawn toward the audience.
Here's a Capitol riddle for you: Representative Lamar Smith, one of the most reflexively anti-immigrant hard-liners in Congress, is sponsoring a bill to flood the agriculture sector with up to half-a-million visas for guest workers.
A remaining riddle for the new chemical warfare inspectors is: Did Iraq really lose, as it claimed, 550 shells filled with mustard gas, which causes chemical burns and blisters?
Tailors pose an odd riddle for our current economy.
