Perimeter Lock

I used the weave of the hanging curtain to ascend from the desk surface to the broad painted sill. Direct morning light cut across the glass. At the center seam of the double-hung frame sat a zinc-alloy sash lock. I gripped the cam lever and applied lateral pressure. It pivoted through a sixty-degree arc, locking into the metal strike plate with a firm click. Through the transparent barrier, the street below showed steady vehicular movement and intersecting footpaths. An extensive sector lies outside this room. I remained crouched beside the latch assembly to map the lines of approach.