We’ve scoured The Lying Detective for details and noticed a few interesting titbits.

Marys real name was Rosamund, which means rose of the world.

Fans know that its never twins but on this occasion, might it just be twins?

4.Is it deliberate that the rug under John and Eurus feet looks very much like a blood stain?

handwritten note from the series four opening credits is of course, Faith Smiths note about her fathers murders.

Still on the opening titles, remember that photograph of Sherlock doubled in the opening credits.

Are wesureits never twins?

The walking stick containing a recording rig fulfils this function inThe Lying Detective, standing in for Watson himself.

7.Do you ever look in the mirror and want to see someone else?

Are we totally, utterly sure its never twins?

At least it shares the same last digits as the phone number E gave to John.

12.Is Sherrinford an institution rather than a person?

and was told he had regular updates, but never were any pronouns used that might give it away.

Sherrinford is the name of prison or psychiatric care home where Eurus was being kept.

That, and the shot of the massive explosion teased in the trailer forThe Final Problem.

14.Check production designerArwel Jones Twitter feedfor a glimpse of how that tilting room effect was achieved.

15.This may well be a coincidence, but look at the cushion Sherlocks head falls onto here.

Its made of tweed, just like the famous hat that comes under such discussion in this episode.

One of his books is also titledHow To Make A Killing.

19.The Culverton Smith wing was opened on the 20thof July 2014.

Blessington the poisoner refers to Sir Arthur Conan DoylesThe Adventure Of The Resident Patient.

Someone bending over a bed caring for/smothering a patient, and perhaps the face of a Babadook-style ghoul.

25.The wallpaper in Sherlocks room at the hospital appears to have TARDIS roundels on it.

More angel than figment, perhaps?

27.As a child, Sherlock set a man-trap to catch Father Christmas.

This isnt a hint or reference, but its fun to know.

28.Mrs Hudson watched the video Mary left for Sherlock at the end ofThe Six Thatchers.

Continuity error or fiendish act from a non-civilian?

29.Must be something comforting about the number three.

People always give up after three says Sherlock of his recording devices.