# t000__ep048__blocks

- **suite / variant:** `` / ``
- **instruction:** Stack the yellow block on the wooden block
- **success:** False
- **control steps:** 1281  (25.4s at 50 Hz)
- **policy inferences:** 221  (replan_steps=6)
- **video:** `blocks/ep048/rollout.mp4`
- **features:** `221` prefix tensors (`prefix`; model=``)

## Semantic timeline

| seconds | control_step | policy_step | phrase |
|---|---|---|---|
| 0.0–3.0 | 0–151 | 0–25 | reaching and grasping yellow block |
| 3.0–6.0 | 152–303 | 25–50 | lifting and moving yellow block |
| 6.0–9.0 | 304–455 | 50–75 | lowering and releasing yellow block off-target |
| 9.0–12.0 | 456–607 | 76–101 | pressing gripper near blocks |
| 12.0–15.0 | 608–759 | 101–126 | hovering near blocks |
| 15.0–18.1 | 760–911 | 126–151 | lingering over blocks |
| 18.1–21.1 | 912–1063 | 152–177 | remaining stationary over blocks |
| 21.1–24.1 | 1064–1215 | 177–202 | hovering idle near blocks |
| 24.1–25.4 | 1216–1280 | 202–213 | idle / no progress |

## Failure

- **yes**
- **onset type:** obvious_mistake
- **onset:** 7.00990099009901 s (00:07.0)
- **frame / control_step:** 354 (policy_step=59, chunk_index=0)
- **coarse onset:** 8.0 s (refined=True)
- **mode:** placement_or_insertion_failure
- **reason:** The robot carries the yellow block to the wooden block but misaligns its position during release, placing the yellow block beside the wooden block instead of stacking it on top.
  Summary: misaligned placement; yellow block placed beside wooden block
- **recovery:** Re-grasp the yellow block, raise it above the wooden block, align it directly over the top surface, and place it down cleanly.
  Summary: re-grasp yellow block; align and stack on wooden block
- **prevention:** Position the yellow block vertically directly above the center of the wooden block before releasing the gripper to ensure a stable stacked placement.
  Summary: center yellow block above wooden block; release directly on top
- **justification:** The robot successfully grasps the yellow block and brings it to the target area, but at around 8.0 seconds, it misaligns the placement attempt, causing the yellow block to slip down beside the wooden block rather than resting on top.