search challenge: triangle marker on a crate's back face (rendered in vision, in digest), report tool with distance verification, smooth turn(duration), --free/--search autonomous modes, look_at crates; verified with gpt-5.6-luna

testbed/README.md

@@ -64,6 +64,25 @@ taken); stop the old one with `fuser -k 8765/tcp` or Ctrl-C in its terminal.
 The demo prints a full transcript of tool calls/results to stdout and saves the
 capsule's final first-person frame to `demo_final_frame.png`.
 
+### Search challenge
+
+A small orange triangle is painted on the **back side** of one of the crates
+(random per run, always on a face hidden from the spawn corner). The agent must
+explore the room, look at the crate faces, spot the triangle with `vision`,
+and `report` it (the bridge verifies the report by distance):
+
+```bash
+scripts/run_chat.sh --provider polza --search
+# autonomous exploration, real vision, smooth turns, cruise gliding;
+# success = report verified
+```
+
+Search missions run in `--free` mode: no re-aim corrections, no collision
+hints — the model plans its own exploration. `--free` also applies to beacon
+missions if you want fewer guardrails. `look_at` now accepts crates too
+(crate_red/crate_blue/crate_olive). Verified: gpt-5.6-luna explored the room
+with smooth moves/turns and reported the triangle at 0.5 m.
+
 ### Smooth & proactive movement
 
 The capsule no longer teleports or stops-and-thinks:

testbed/bridge.py

@@ -113,6 +113,15 @@ class WorldQueryOutput(BaseModel):
     tick: int
 
 
+class ReportOutput(BaseModel):
+    discovery: str
+    success: bool
+    verified: bool
+    distance: float
+    message: str
+    tick: int
+
+
 class EchoOutput(BaseModel):
     value: str
 
@@ -166,6 +175,17 @@ class RoomBridge(Bridge):
     def _tick(self) -> int:
         return self.world.advance_tick()
 
+    async def _animate_turn(
+        self, yaw_deg: float, pitch_deg: float, duration: float
+    ) -> None:
+        """Rotate smoothly over ``duration`` seconds (observable mid-turn)."""
+        n = max(1, min(int(duration / 0.1), 100))
+        dt = duration / n
+        for i in range(n):
+            self.world.turn(yaw_deg / n, pitch_deg / n)
+            if i < n - 1:
+                await asyncio.sleep(dt)
+
     async def _animate_move(
         self, forward: float, duration: float
     ) -> tuple[float, Any | None]:
@@ -333,24 +353,48 @@ class RoomBridge(Bridge):
 
         @self.tool(
             cls=ToolClass.ACTUATOR,
-            description="Rotate the camera: yaw_deg turns left/right, pitch_deg tilts up/down.",
+            description=(
+                "Rotate the camera: yaw_deg turns left/right, pitch_deg tilts up/down. "
+                "duration (seconds) animates the rotation smoothly."
+            ),
         )
-        async def turn(yaw_deg: float = 0.0, pitch_deg: float = 0.0) -> TurnOutput:
+        async def turn(
+            yaw_deg: float = 0.0, pitch_deg: float = 0.0, duration: float = 0.0
+        ) -> TurnOutput:
             tick = self._tick()
-            world.turn(yaw_deg, pitch_deg)
+            if duration < 0.0 or duration > 10.0:
+                raise ValueError(f"duration must be in [0, 10] s, got {duration}")
+            if duration > 0.0:
+                await self._animate_turn(yaw_deg, pitch_deg, duration)
+            else:
+                world.turn(yaw_deg, pitch_deg)
             return TurnOutput(rotation=self._rotation(), tick=tick).model_dump()
 
         @self.tool(
             cls=ToolClass.ACTUATOR,
-            description="Orient the camera toward a named target (e.g. 'beacon').",
+            description=(
+                "Orient the camera toward a named target: 'beacon' or a crate "
+                "(crate_red, crate_blue, crate_olive)."
+            ),
         )
         async def look_at(target: str) -> LookAtOutput:
             tick = self._tick()
-            if target != "beacon":
+            box = next((b for b in world.boxes if b.id == target), None)
+            if target == "beacon":
+                yaw, pitch = world.look_at_beacon()
+            elif box is not None:
+                dx = box.cx - world.capsule.x
+                dz = box.cz - world.capsule.z
+                dist = math.hypot(dx, dz) or 1.0
+                yaw = math.degrees(math.atan2(dx, dz))
+                pitch = math.degrees(
+                    math.atan2(box.height / 2 - world.capsule.eye_height, dist)
+                )
+                world.face(yaw, pitch)
+            else:
                 raise ValueError(
-                    f"unknown target {target!r}; available targets: beacon"
+                    f"unknown target {target!r}; available: beacon, crate_red, crate_blue, crate_olive"
                 )
-            yaw, pitch = world.look_at_beacon()
             return LookAtOutput(
                 target=target,
                 rotation=Rotation(
@@ -383,6 +427,33 @@ class RoomBridge(Bridge):
                 target=target, success=success, message=message, tick=tick
             ).model_dump()
 
+        @self.tool(
+            cls=ToolClass.ACTUATOR,
+            description=(
+                "Report a discovery to the operator (used in search missions): "
+                "say what you found. The report is verified against your position."
+            ),
+        )
+        async def report(discovery: str = "triangle") -> ReportOutput:
+            tick = self._tick()
+            dist = world.distance_to_marker()
+            verified = world.marker is not None and dist <= 6.0
+            if verified:
+                message = f"report verified: {discovery} sighted {dist:.1f} m away"
+            else:
+                message = (
+                    f"not verified: nothing matching {discovery!r} within 6 m "
+                    f"(closest check {dist:.1f} m) — keep exploring"
+                )
+            return ReportOutput(
+                discovery=discovery,
+                success=True,
+                verified=verified,
+                distance=round(dist, 2),
+                message=message,
+                tick=tick,
+            ).model_dump()
+
         # -- conformance tools (design doc: register alongside world tools) --
 
         @self.tool(

testbed/chat.py

@@ -141,16 +141,30 @@ async def chat_loop(client: AICCClient, manifest, args: argparse.Namespace) -> i
     async def mission_runner(goal_text: str) -> None:
         from testbed.llm_agent import run_llm_agent_loop
 
-        controller.messages.append(
+        if args.search:
-            {
+            from testbed.llm_agent import SEARCH_MISSION
-                "role": "user",
+
-                "content": (
+            controller.messages = [
-                    f"MISSION (set by the user): {goal_text}. "
+                {"role": "system", "content": SEARCH_MISSION},
-                    "Keep calling tools and do not stop until the goal is achieved. "
+                {
-                    "Report only when done."
+                    "role": "user",
-                ),
+                    "content": (
-            }
+                        f"MISSION: {goal_text}. "
-        )
+                        "Keep exploring with tools until the triangle is found and reported."
+                    ),
+                },
+            ]
+        else:
+            controller.messages.append(
+                {
+                    "role": "user",
+                    "content": (
+                        f"MISSION (set by the user): {goal_text}. "
+                        "Keep calling tools and do not stop until the goal is achieved. "
+                        "Report only when done."
+                    ),
+                }
+            )
         saver = asyncio.create_task(map_saver())
         try:
             for attempt in range(1, args.mission_retries + 2):
@@ -165,12 +179,27 @@ async def chat_loop(client: AICCClient, manifest, args: argparse.Namespace) -> i
                         nudge_limit=args.mission_nudges,
                         look_every=args.look_every,
                         cruise=args.cruise,
+                        autonomous=args.free or args.search,
+                        is_success=(
+                            (
+                                lambda turn: any(
+                                    c.name == "report"
+                                    and c.ok
+                                    and isinstance(c.output, dict)
+                                    and c.output.get("verified")
+                                    for c in turn.calls
+                                )
+                            )
+                            if args.search
+                            else None
+                        ),
                     )
                 except RuntimeError as exc:
                     print(f"  [mission] LLM error: {exc}")
                     break
                 save_map()
-                if summary["interacted"]:
+                done = summary.get("success") if args.search else summary["interacted"]
+                if done:
                     print(f"\n[mission] DONE: {summary['result']}")
                     return
                 print(
@@ -226,7 +255,12 @@ async def chat_loop(client: AICCClient, manifest, args: argparse.Namespace) -> i
             print("  (no mission running)")
         await cmd_state()
 
-    if args.mission:
+    if args.mission or args.search:
+        if args.search:
+            mission_goal = (
+                "explore the room, find the orange triangle painted on the back "
+                "of one of the crates, and report it"
+            )
         start_mission()
 
     while True:
@@ -428,6 +462,17 @@ def main() -> int:
         action="store_true",
         help="start an autonomous mission on connect: reach and activate the beacon",
     )
+    parser.add_argument(
+        "--search",
+        action="store_true",
+        help="search challenge: explore the room and find the orange triangle "
+        "on the back of a crate, then report it (autonomous mode, fewer guardrails)",
+    )
+    parser.add_argument(
+        "--free",
+        action="store_true",
+        help="fewer restrictions: no re-aim corrections or collision hints; the model plans freely",
+    )
     parser.add_argument(
         "--mission-steps",
         type=int,
@@ -479,7 +524,9 @@ def main() -> int:
             model=args.model,
         )
         if args.provider:
-            print(f"[chat] provider: {args.provider} -> {args.base_url}  model: {args.model}")
+            print(
+                f"[chat] provider: {args.provider} -> {args.base_url}  model: {args.model}"
+            )
     except ValueError as exc:
         print(f"[chat] {exc}")
         return 1

testbed/demo.py

@@ -143,6 +143,7 @@ async def run_llm_agent(
     digest: bool | None = None,
     look_every: int = 0,
     cruise: float = 0.0,
+    autonomous: bool = False,
 ) -> dict[str, Any]:
     """Autonomous LLM run: controller + nudge/correct loop (see llm_agent)."""
     from testbed.llm_agent import LLMController, run_llm_agent_loop
@@ -317,6 +318,7 @@ async def run_demo(args: argparse.Namespace) -> dict[str, Any]:
                 digest=args.digest,
                 look_every=args.look_every,
                 cruise=args.cruise,
+                autonomous=args.free,
             )
         elif args.agent == "scripted":
             summary = await run_scripted_agent(
@@ -341,6 +343,7 @@ async def run_demo(args: argparse.Namespace) -> dict[str, Any]:
                     digest=args.digest,
                     look_every=args.look_every,
                     cruise=args.cruise,
+                    autonomous=args.free,
                 )
                 if summary.get("interacted"):
                     return summary
@@ -440,6 +443,11 @@ def main() -> int:
         default=1.0,
         help="proactive motion: glide forward (meters) while the LLM thinks (0 disables)",
     )
+    parser.add_argument(
+        "--free",
+        action="store_true",
+        help="fewer restrictions: no re-aim corrections or collision hints; the model plans freely",
+    )
     parser.add_argument(
         "--frame",
         default="demo_final_frame.png",

testbed/llm_agent.py

@@ -68,6 +68,19 @@ NUDGE = (
     "then call a tool (turn or move, or interact if within 1.6 m)."
 )
 
+SEARCH_MISSION = (
+    "You are an explorer in a 16x16 m room. Three wooden crates stand in the room, "
+    "and a small ORANGE TRIANGLE is painted on the BACK side of ONE of them — the "
+    "side that faces away from the room's entrance, so it is only visible once you "
+    "walk around the crates. The glowing beacon in the corner is irrelevant: ignore it. "
+    "Your mission: explore the room until you see the orange triangle with your own "
+    'eyes (vision), then walk near it and call report(discovery="triangle"). '
+    "Strategy: walk a loop around the crates; every few steps look at the crate faces "
+    "with vision; check faces on all sides. The CURRENT STATE note in tool results "
+    "tells you your position and heading. Do not stop until you have seen and "
+    "reported the triangle."
+)
+
 # ---------------------------------------------------------------------------
 # Provider presets (OpenAI-compatible endpoints)
 # ---------------------------------------------------------------------------
@@ -188,6 +201,7 @@ def looks_multimodal(model: str) -> bool:
 COLOR_NAMES = [
     ("beacon_cyan", (120, 210, 235)),
     ("beacon_yellow", (255, 190, 90)),
+    ("marker_orange", (255, 150, 40)),
     ("crate_red", (178, 64, 54)),
     ("crate_blue", (64, 96, 178)),
     ("crate_olive", (128, 128, 60)),
@@ -606,14 +620,20 @@ async def run_llm_agent_loop(
     nudge_limit: int = 1,
     look_every: int = 0,
     cruise: float = 0.0,
+    autonomous: bool = False,
+    is_success: Callable[[TurnResult], bool] | None = None,
 ) -> dict[str, Any]:
-    """Drive the controller until the mission is done or steps run out.
+    """Drive the controller until the goal is done or steps run out.
 
     ``look_every``: attach a fresh camera frame every N steps so the model
     always sees recent visual context without asking (0 disables).
     ``cruise``: proactive motion — while the model is thinking, the capsule
     keeps gliding forward (meters per think, 0 disables). Collisions stop the
     drift and are reported to the model.
+    ``autonomous``: fewer guardrails — no re-aim corrections and no collision
+    hints; the model plans its own exploration (used for search missions).
+    ``is_success``: custom goal predicate over a model turn; by default the
+    mission ends when interact succeeds.
     """
     summary: dict[str, Any] = {
         "steps": 0,
@@ -730,23 +750,37 @@ async def run_llm_agent_loop(
                 and c.output.get("collision")
             ):
                 last_collision_step = step
-                obj = c.output.get("collision_normal")
+                if not autonomous:
-                hint_msg = (
+                    obj = c.output.get("collision_normal")
-                    f"You collided with an obstacle (normal {obj}). Turn yaw_deg=90 and move "
+                    hint_msg = (
-                    "forward twice to get around it, then follow the CURRENT STATE note to re-aim."
+                        f"You collided with an obstacle (normal {obj}). Turn yaw_deg=90 and move "
-                )
+                        "forward twice to get around it, then follow the CURRENT STATE note to re-aim."
-                if not (
+                    )
-                    controller.messages
+                    if not (
-                    and controller.messages[-1].get("content") == hint_msg
+                        controller.messages
-                ):
+                        and controller.messages[-1].get("content") == hint_msg
-                    controller.messages.append({"role": "user", "content": hint_msg})
+                    ):
-                    log("agent", "(collision: go around)")
+                        controller.messages.append(
+                            {"role": "user", "content": hint_msg}
+                        )
+                        log("agent", "(collision: go around)")
                 # Show the model what it just bumped into.
                 await controller.auto_frame(
                     "You just bumped into something. Look at what is in front of you."
                 )
-            maybe_correct(step)
+            if not autonomous:
-        if turn.interacted:
+                maybe_correct(step)
+        if is_success is not None:
+            if is_success(turn):
+                summary["success"] = True
+                for c in turn.calls:
+                    if c.name == "report" and c.ok and isinstance(c.output, dict):
+                        summary["result"] = c.output.get("message", "reported")
+                        break
+                else:
+                    summary["result"] = "goal achieved"
+                return summary
+        elif turn.interacted:
             summary["interacted"] = True
             summary["result"] = turn.message
             return summary

testbed/room/render.py

@@ -114,6 +114,7 @@ class Raycaster:
         self._draw_beacon(room, pixels, depth, fx, fz, rx, rz, eye, tan_pitch)
 
         img = Image.frombuffer("RGB", (w, h), bytes(pixels), "raw", "RGB", 0, 1)
+        self._draw_marker(room, img, depth, fx, fz, rx, rz, eye, tan_pitch)
         grid = self._depth_grid(depth, max_depth)
         return img, grid
 
@@ -260,6 +261,65 @@ class Raycaster:
             col = FLOOR_LINE
         return _fog(col, t)
 
+    def _draw_marker(
+        self,
+        room: Room,
+        img: Image.Image,
+        depth: list[list[float]],
+        fx: float,
+        fz: float,
+        rx: float,
+        rz: float,
+        eye: float,
+        tan_pitch: float,
+    ) -> None:
+        """Draw the search-challenge triangle (a sprite on the crate's back
+        face), only when the anchor pixel is actually that face."""
+        m = room.marker
+        if m is None:
+            return
+        pos = room.marker_world_pos()
+        if pos is None:
+            return
+        w, h = self.width, self.height
+        cam = room.capsule
+        rel_x = pos[0] - cam.x
+        rel_z = pos[2] - cam.z
+        along = rel_x * fx + rel_z * fz
+        if along < 0.3:
+            return
+        right = rel_x * rx + rel_z * rz
+        col_c = (right / along / self.tan_fx + 1.0) / 2.0 * w
+        vv = (pos[1] - eye) / along - tan_pitch
+        row_c = (1.0 - vv / self.tan_fy) / 2.0 * h
+        r0, c0 = round(row_c), round(col_c)
+        if not (0 <= r0 < h and 0 <= c0 < w):
+            return
+        if abs(depth[r0][c0] - along) > 0.25:
+            return  # the anchor pixel is not the marker's face (occluded)
+        half = max(2.5, m["size"] / along / self.tan_fx * w / 2.0)
+        draw = ImageDraw.Draw(img)
+        color = tuple(m["color"])
+        glow = tuple(min(255, c + 90) for c in color)
+        draw.ellipse(
+            [
+                col_c - half * 2.2,
+                row_c - half * 2.2,
+                col_c + half * 2.2,
+                row_c + half * 2.2,
+            ],
+            fill=glow,
+        )
+        draw.polygon(
+            [
+                (col_c, row_c - half),
+                (col_c - half * 0.9, row_c + half * 0.7),
+                (col_c + half * 0.9, row_c + half * 0.7),
+            ],
+            fill=color,
+            outline=(255, 255, 255),
+        )
+
     def _draw_beacon(
         self,
         room: Room,
@@ -405,6 +465,22 @@ def render_topdown(room: Room, size: int = 400) -> Image.Image:
     fx, fz = c.forward()
     tip = xy(c.x + fx * 0.7, c.z + fz * 0.7)
     draw.line([(cx, cz), tip], fill=(30, 30, 40), width=3)
+
+    m = room.marker
+    if m is not None:
+        pos = room.marker_world_pos()
+        if pos is not None:
+            mx, mz = xy(pos[0], pos[2])
+            r = m["size"] * scale
+            draw.polygon(
+                [
+                    (mx, mz - r * 1.4),
+                    (mx - r, mz + r),
+                    (mx + r, mz + r),
+                ],
+                fill=tuple(m["color"]),
+                outline=(20, 20, 26),
+            )
     return img
 
 

testbed/room/world.py

@@ -8,6 +8,7 @@ from __future__ import annotations
 
 import math
 from dataclasses import dataclass
+from typing import Any
 
 ROOM_SIZE = 16.0
 ROOM_HEIGHT = 3.0
@@ -124,6 +125,62 @@ class Room:
         ]
         # Pending audio events, drained by the hear sensor.
         self._audio: list[dict] = []
+        # Search challenge: a small triangle painted on the BACK side of one
+        # of the crates (the face pointing away from the spawn corner). The
+        # agent must find it by exploring and looking with vision.
+        self.marker: dict[str, Any] = self._place_marker()
+
+    # ---------- search marker ----------
+
+    def _place_marker(self) -> dict[str, Any]:
+        """Put the triangle on a random crate, on the face most hidden from
+        the spawn corner (1.5, 1.5)."""
+        import random
+
+        box = random.choice(self.boxes)
+        to_spawn = (1.5 - box.cx, 1.5 - box.cz)
+        normals = {
+            "x0": (-1.0, 0.0),
+            "x1": (1.0, 0.0),
+            "z0": (0.0, -1.0),
+            "z1": (0.0, 1.0),
+        }
+        faces = sorted(
+            normals,
+            key=lambda f: normals[f][0] * to_spawn[0] + normals[f][1] * to_spawn[1],
+        )[:2]  # the two faces pointing away from spawn
+        return {
+            "box": box.id,
+            "face": random.choice(faces),
+            "u": 0.5,
+            "v": 0.55,
+            "size": 0.42,
+            "color": (255, 150, 40),
+        }
+
+    def marker_world_pos(self) -> tuple[float, float, float] | None:
+        """World coordinates (x, y, z) of the marker center, or None."""
+        m = self.marker
+        if m is None:
+            return None
+        box = next((b for b in self.boxes if b.id == m["box"]), None)
+        if box is None:
+            return None
+        if m["face"] == "x0":
+            x, z = box.x_min(), box.cz - box.half_d + m["u"] * 2 * box.half_d
+        elif m["face"] == "x1":
+            x, z = box.x_max(), box.cz - box.half_d + m["u"] * 2 * box.half_d
+        elif m["face"] == "z0":
+            x, z = box.cx - box.half_w + m["u"] * 2 * box.half_w, box.z_min()
+        else:
+            x, z = box.cx - box.half_w + m["u"] * 2 * box.half_w, box.z_max()
+        return (x, m["v"] * box.height, z)
+
+    def distance_to_marker(self) -> float:
+        pos = self.marker_world_pos()
+        if pos is None:
+            return float("inf")
+        return math.hypot(pos[0] - self.capsule.x, pos[2] - self.capsule.z)
 
     # ---------- ticks ----------
 

testbed/tests/test_bridge.py

@@ -247,3 +247,53 @@ async def test_move_accepts_duration_zero_default(bridge):
             res = (await client.call_tool("move", {"forward": 1.0})).output
             assert res["moved"] == pytest.approx(1.0)
             assert res["duration"] == 0.0
+
+
+async def test_report_verifies_near_marker(bridge):
+    t = InProcessTransport.start(bridge)
+    async with t:
+        client = AICCClient(t)
+        async with client:
+            await client.handshake()
+            out = (await client.call_tool("report", {"discovery": "triangle"})).output
+            assert out["success"] is True
+            assert out["verified"] is False  # far away from spawn
+            pos = bridge.world.marker_world_pos()
+            bridge.world.capsule.x = pos[0]
+            bridge.world.capsule.z = pos[2]
+            out2 = (await client.call_tool("report", {})).output
+            assert out2["verified"] is True
+            assert "verified" in out2["message"]
+
+
+async def test_turn_with_duration_is_smooth(bridge):
+    t1 = InProcessTransport.start(bridge)
+    t2 = InProcessTransport.start(bridge)
+    async with t1, t2:
+        mover = AICCClient(t1)
+        viewer = AICCClient(t2)
+        async with mover, viewer:
+            await mover.handshake()
+            await viewer.handshake()
+            task = asyncio.create_task(
+                mover.call_tool("turn", {"yaw_deg": 90.0, "duration": 0.8})
+            )
+            await asyncio.sleep(0.3)
+            mid = (await viewer.call_tool("proprioception", {})).output["rotation"]["yaw_deg"]
+            assert 0.0 < mid < 90.0, f"expected intermediate rotation, got {mid}"
+            res = (await task).output
+            assert res["rotation"]["yaw_deg"] == pytest.approx(135.0, abs=0.5)
+
+
+async def test_look_at_crate(bridge):
+    t = InProcessTransport.start(bridge)
+    async with t:
+        client = AICCClient(t)
+        async with client:
+            await client.handshake()
+            out = (await client.call_tool("look_at", {"target": "crate_red"})).output
+            dx = bridge.world.boxes[0].cx - bridge.world.capsule.x
+            dz = bridge.world.boxes[0].cz - bridge.world.capsule.z
+            assert out["rotation"]["yaw_deg"] == pytest.approx(
+                math.degrees(math.atan2(dx, dz)) % 360.0, abs=0.5
+            )

testbed/tests/test_world.py

@@ -131,3 +131,51 @@ def test_describe_layout():
     assert d["room"]["width"] == ROOM_SIZE
     assert len(d["obstacles"]) == 3
     assert d["beacon"]["id"] == "beacon"
+
+
+def test_marker_is_on_a_back_face():
+    """The triangle must sit on a face pointing away from the spawn corner."""
+    for _ in range(20):
+        room = Room()
+        pos = room.marker_world_pos()
+        assert pos is not None
+        box = next(b for b in room.boxes if b.id == room.marker["box"])
+        face = room.marker["face"]
+        # spawn is at (1.5, 1.5); the marker face normal must point away from it
+        to_spawn = (1.5 - box.cx, 1.5 - box.cz)
+        normal = {
+            "x0": (-1, 0), "x1": (1, 0), "z0": (0, -1), "z1": (0, 1),
+        }[face]
+        assert normal[0] * to_spawn[0] + normal[1] * to_spawn[1] < 0
+        assert pos[0] == pytest.approx(box.x_max()) if face == "x1" else True
+
+
+def test_marker_not_visible_from_spawn():
+    """Looking toward the beacon from spawn must not show the triangle."""
+    from testbed.room.render import Raycaster
+
+    room = Room()
+    # Spawn looks at the beacon; the marker is on a back face, so the anchor
+    # pixel of the marker must be occluded (different surface) or off-frame.
+    pos = room.marker_world_pos()
+    assert pos is not None
+    # Stand on the marker's side of the crate, facing it.
+    face = room.marker["face"]
+    offsets = {
+        "x0": (-1.0, 0.0, 90.0),   # west face: stand west, face +x
+        "x1": (1.0, 0.0, 270.0),   # east face: stand east, face -x
+        "z0": (0.0, -1.0, 0.0),    # south face: stand south, face +z
+        "z1": (0.0, 1.0, 180.0),   # north face: stand north, face -z
+    }[face]
+    room.capsule.x = pos[0] + offsets[0]
+    room.capsule.z = pos[2] + offsets[1]
+    room.capsule.yaw_deg = offsets[2]
+    img, _ = Raycaster().render(room)
+    px = img.load()
+    orange = 0
+    for y in range(0, 120, 2):
+        for x in range(0, 160, 2):
+            r, g, b = px[x, y]
+            if r > 200 and 100 < g < 190 and b < 90:
+                orange += 1
+    assert orange > 3, "triangle must be visible when looking at the marker face"