With the benefit of hindsight it may not have counted among the very best of my ideas. But at the time, my friend Sherlock Holmes was unoccupied by any case, and therefore querulous. Weary of Mrs. Hudson's cheese soufflés, tired of indexes and polyphonic motets, he turned to smoking himself into a black-suited kipper. It was with this state in mind, then, that I hesitated upon my return home that April afternoon, to drop through a small trinket shop recently sprung up on one of London's busy streets. I emerged, clutching my small bundle, and made my way back to 221B Baker Street.

When I entered our sitting-room I discovered Holmes pacing a hole in the hearth rug, his teeth clenched around his old black clay, his hands thrust deep into his trouser pockets. He looked up with one eye scowling.

"I am back," I said, removing my hat and my coat and stepping closer to the fire – for although it was now Spring the air still carried a nip, and our large room most often tended to the chilly. "How long have you been stamping around like that?"

He stopped, as if he had not noticed that he had been as a perpetual motion machine. He looked down at his feet, confused.

"I am not sure?" he offered, finally. "Perhaps the duration of five pipes?"

"Five pipes! It is no wonder that the air is a fug." I swatted around me. I delved into my right pocket and drew forth the package. I proffered it to him. "Here. I have brought you something."

Holmes eyed it suspiciously. "What is it?" he asked. He drew closer, bent forward and sniffed. "It is not edible," he declared, with an air of relief. He accepted it with a sharp nod. "Thank you."

I watched as he unravelled the wrapping, tussling with the tape. At length he produced the content within and turned it over in his hands.

"You brought me a block of wood." He sounded baffled.

"No, no," I said, shaking my head. "Examine it a little more closely, Holmes."

He did so, frowning. He shook it.

"It rattles," said he, disappointed. "It is broken, Watson."

"It is not broken," I told my friend. "That is how it is meant to be. It is a puzzle."

Holmes looked down once more. Again, he shook it.

"It is a block of wood that rattles," said he, plaintively. "I am unable to see what could possibly be at all puzzling about that."

"No, Holmes," I replied, pointing to a corner of the rectangular block. "See, there is a little round hole at one side. That is where the marble must come out. It is a puzzle game. You have to release the marble from its maze."

I could not tell if Holmes found my explanation of any value, or if he now considered me a sorry lunatic, for his scowl deepened and he proceeded in worrying at the object as if it might itself utter an articulate sentence if he persisted long enough.

"I don't understand," said he, finally. "I cannot see the maze, or the marble. Who was so careless as to mislay their marble inside a solid block of wood in such a manner?"

"No, Holmes," I said, by now regrettably exasperated. "Nobody has lost their marble. Although I fear that I might very soon be losing all of mine. My dear fellow, it is a puzzle. A marble is within the block of wood, inside an intricate maze. You must tilt and turn the block, and work out the path which the marble is taking, so that eventually it will fall out from the hole. And that will mean that you have solved the puzzle."

I sat down heavily in my chair. I wondered why a simple friendly gesture had to evolve into such confusion. But this was so often the way with my dear celebrated friend, it seemed to me.

"Oh," said Holmes. He lifted the block and set the hole cast in the side of it to his right eye, attempting to peer into its inner sanctum. He tilted it gingerly to one side, listening intently to the scuttle of the marble deep within. He looked at me. "Am I doing it right?" he asked.

I chuckled. "I am deferring judgement until I see actual evidence of the marble," I said. "It might take you a little while, Holmes."

He huffed audibly. "It will not," said he. "I shall have it out within a few moments."

He sat down in his chair and proceeded to twist, turn and listen to his new object of amusement. I leaned back and lit a pipe and watched his progress. Once or twice I believed that he must have it – for he exhaled in quiet triumph – but then his prize rolled away from him into the depths once more, for he snarled and shook the block in deep frustration. After a considerable interval he tossed up his head.

"It is broken, Watson," he said, thwarted and cross. "The wretched marble is stuck, or there is no way out for it at all and I am wasting my time."

I wondered for a brief moment if he might throw it upon the floor and crush it with his foot.

"Well, that is the nature of a puzzle," I said, comfortingly. "They are not intended to be solved within minutes. I thought that it might keep you entertained, Holmes. Relieve you of your ennui."

"It is not relieving me," said Holmes. "It is driving me utterly mad. Therefore, I could not say with any conviction that I am remotely entertained by it. Does it have an emergency button?" He twisted it around again to look.

"I do not believe so." I sighed. "You do not have to play with it if you would rather not, you know. I just thought that you might enjoy it, for it has a logic to it, after all. At any rate, it will make a handsome paperweight if nothing else."

Holmes nodded, oblivious to my sarcasm. "I suppose I should be grateful that it is not a jigsaw puzzle," he said. "But of course you know me better than that, Watson."

"I should never have dared to purchase such an article for you, Holmes," I agreed, a cold shiver running down my spine at the mere thought of it.

"Or Jackstraws," he added. "Or, perish the hellish thought, Tiddlywinks."

"If there had been space enough in this room then I might have invested in a wooden rocking horse," I said dryly. "You would have gotten many hours of enjoyment out of that."

Holmes tutted. "Now you are just being facetious," said he. Then he paused, turning his head to the one side in rumination. "I never had a rocking horse," he said, softly.

"Look," I said, "pass the puzzle across to me. Would you like me to take a try at it?"

He proffered it cautiously, eyeing it anxiously as I turned it over in my hands.

"I believe that I must have done the greater part of it," he said, craning his neck to look.

"What rot," I replied, beginning to laugh, for the expression on his face was that of a petulant child. "You just would rather I not beat the puzzle before you do, Holmes, isn't that right?"

He chose not to reply, instead turning his attention to attacking the burning fire coals with the poker. I concentrated upon the block, but I confess that I was no greater a fellow of logic than my friend on this occasion, for the marble resolutely refused to come forth from its wooden cell. For such a small thing, it was intricate indeed.

"Shall I fetch a hammer?" my friend enquired.

"No, Holmes."

"We could prise it open with the butter knife?"

"That would be hardly sensible, my dear fellow."

I placed the block to the one side of me with a small sigh of surrender. Holmes's relief was quite palpable.

"Later," I said. "After dinner, perhaps, when we are more relaxed to spend the time with it."

"Any fellow who calls such an object relaxing should be locked in a dark room and kept under close supervision," said my friend – rather unnecessarily, I thought. We both turned our attentions to other matters.

At seven o'clock, Mrs. Hudson brought us two steaming bowls of fish stew. Turning around to leave us to our meal, she espied the puzzle sitting atop the table.

"Oh is that what I think it is?" asked our dear landlady, with a curious smile. "I do so love those."

Holmes paused with a spoonful of stew halfway to his lips.

"Mrs. Hudson," said he, "if you are able to release that confounded marble, then I should say that you -"

But then he stopped short. I was already staring. For with a series of deft turns and tilts, Mrs. Hudson was now holding a delicate green marble within the palm of her weathered hand.

"There!" said she. "What a bonny thing it is! Shall I replace it, Mr. Holmes?"

"No!" said Holmes. His spoon had dropped into his bowl, spattering small blots upon the tablecloth. "No, please, that is quite all right. Thank you, Mrs. Hudson. Yes, leave it there, upon the edge. Thank you."

Our landlady left us to our meal. I looked at my friend and began to laugh. He was still rapt upon the green marble now sitting beside its wooden prison.

"I believe I must have done the greater part of it," he repeated, slowly.

"Yes, Holmes," I said, picking up my spoon and commencing to eat. "I am certain that you must have done. And at least now we very definitely know that it was not stuck, and that the maze inside is a true one."

"The greater part of it," he said again, almost under his breath.

"It must have been almost at the exit point," I agreed.

And we ate our fish stew, which was very delicious; and we found, at a later date, that a handsomely polished wooden block with a green marble rattling inside it really does make a most admirable paperweight.