# t000__ep026__blocks

- **suite / variant:** `` / ``
- **instruction:** Stack the yellow block on the wooden block
- **success:** False
- **control steps:** 577  (11.4s at 51 Hz)
- **policy inferences:** 99  (replan_steps=6)
- **video:** `blocks/ep026/rollout.mp4`
- **features:** `99` prefix tensors (`prefix`; model=``)

## Semantic timeline

| seconds | control_step | policy_step | phrase |
|---|---|---|---|
| 0.0–3.0 | 0–151 | 0–25 | reaching for and grasping yellow block |
| 3.0–6.0 | 152–303 | 25–50 | lifting and carrying yellow block |
| 6.0–9.0 | 304–455 | 50–75 | releasing yellow block beside wooden block |
| 9.0–11.4 | 456–576 | 76–96 | hovering above wooden block |

## Failure

- **yes**
- **onset type:** obvious_mistake
- **onset:** 7.411067193675889 s (00:07.4)
- **frame / control_step:** 375 (policy_step=62, chunk_index=3)
- **coarse onset:** 5.8 s (refined=True)
- **mode:** placement_or_insertion_failure
- **reason:** The robot brought the yellow block over the wooden block but misaligned the placement, causing the yellow block to slide off the side and fall onto the table.
  Summary: misaligned block placement; object fell off target
- **recovery:** Re-grasp the yellow block from the table surface, align it directly over the center of the wooden block, and stack it cleanly.
  Summary: re-grasp yellow block; align and stack on wooden block
- **prevention:** Align the yellow block directly over the center of the wooden block before opening the gripper to ensure a stable stacked placement.
  Summary: align block centrally; release gently on top
- **justification:** At around 5.8 seconds, the robot released the yellow block over the edge of the wooden block without proper centering, causing the yellow block to fall onto the table next to the target block instead of remaining stacked on top.