My friend’s plans were gradually revealing themselves.  From this convenient retreat, the watchers were being watched and the trackers tracked.  That angular shadow up yonder was the bait, and we were the hunters.  In silence we stood together in the darkness and watched the hurrying figures who passed and repassed in front of us.  Holmes was silent and motionless; but I could tell that he was keenly alert, and that his eyes were fixed intently upon the stream of passers-by.  It was a bleak and boisterous night and the wind whistled shrilly down the long street.  Many people were moving to and fro, most of them muffled in their coats and cravats.  Once or twice it seemed to me that I had seen the same figure before, and I especially noticed two men who appeared to be sheltering themselves from the wind in the doorway of a house some distance up the street.  I tried to draw my companion’s attention to them; but he gave a little ejaculation of impatience, and continued to stare into the street.  More than once he fidgeted with his feet and tapped rapidly with his fingers upon the wall.  It was evident to me that he was becoming uneasy, and that his plans were not working out altogether as he had hoped.  At last, as midnight approached and the street gradually cleared, he paced up and down the room in uncontrollable agitation.  I was about to make some remark to him, when I raised my eyes to the lighted window, and again experienced almost as great a surprise as before.  I clutched Holmes’s arm, and pointed upward.

“The shadow has moved!” I cried.

It was indeed no longer the profile, but the back, which was turned towards us.

Three years had certainly not smoothed the asperities of his temper or his impatience with a less active intelligence than his own.

“Of course it has moved,” said he.  “Am I such a farcical bungler, Watson, that I should erect an obvious dummy, and expect that some of the sharpest men in Europe would be deceived by it?  We have been in this room two hours, and Mrs. Hudson has made some change in that figure eight times, or once in every quarter of an hour.  She works it from the front, so that her shadow may never be seen.  Ah!” He drew in his breath with a shrill, excited intake.  In the dim light I saw his head thrown forward, his whole attitude rigid with attention.  Outside the street was absolutely deserted.  Those two men might still be crouching in the doorway, but I could no longer see them.  All was still and dark, save only that brilliant yellow screen in front of us with the black figure outlined upon its centre.  Again in the utter silence I heard that thin, sibilant note which spoke of intense suppressed excitement.  An instant later he pulled me back into the blackest corner of the room, and I felt his warning hand upon my lips.  The fingers which clutched me were quivering.  Never had I known my friend more moved, and yet the dark street still stretched lonely and motionless before us.