This is a scene I drew based on a passage from The Sign of Four, but with Sherlock and John in their BBC forms. Here's the passage I based it off of:

"Ah, that is more than I can tell. Since, however, we had already determined that Small came from the Andamans, it is not so very wonderful that this islander should be with him. No doubt we shall know all about it in time. Look here, Watson; you look regularly done. Lie down there on the sofa and see if I can put you to sleep."

He took up his violin from the corner, and as I stretched myself out he began to play some low, dreamy, melodious air - his own, no doubt, for he had a remarkable gift for improvisation. I have a vague remembrance of his gaunt limbs, his earnest face and the rise and fall of his bow. Then I seemed to be floated peacefully away upon a soft sea of sound until I found myself in dreamland, with the sweet face of Mary Morstan looking down upon me.

It was late in the afternoon before I woke, strengthened and refreshed. Sherlock Holmes still sat exactly as I had left him, save that he had laid aside his violin and was deep in a book. He looked across at me as I stirred, and his face was dark and troubled.

"You have slept soundly," he said. "I feared our talk would wake you."