# t000__ep027__blocks

- **suite / variant:** `` / ``
- **instruction:** Stack the yellow block on the wooden block
- **success:** False
- **control steps:** 645  (12.8s at 50 Hz)
- **policy inferences:** 112  (replan_steps=6)
- **video:** `blocks/ep027/rollout.mp4`
- **features:** `112` prefix tensors (`prefix`; model=``)

## Semantic timeline

| seconds | control_step | policy_step | phrase |
|---|---|---|---|
| 0.0–3.0 | 0–150 | 0–25 | lowering arm toward yellow block |
| 3.0–6.0 | 151–301 | 25–50 | grasping and lifting yellow block |
| 6.0–9.0 | 302–452 | 50–75 | placing block on wooden block |
| 9.0–12.0 | 453–603 | 75–100 | retracting gripper and hovering |
| 12.0–12.8 | 604–644 | 100–107 | lowering toward table |

## Failure

- **yes**
- **onset type:** obvious_mistake
- **onset:** 5.059760956175299 s (00:05.1)
- **frame / control_step:** 254 (policy_step=42, chunk_index=2)
- **coarse onset:** 8.0 s (refined=True)
- **mode:** placement_or_insertion_failure
- **reason:** The robot attempted to stack the yellow block on the wooden block, but misaligned the block upon release, causing it to slide off onto the table surface.
  Summary: misaligned block placement; block sliding off target
- **recovery:** Re-grasp the fallen yellow block from the table surface, align it directly over the center of the wooden block, and release it gently.
  Summary: re-grasp yellow block; place on wooden block
- **prevention:** Ensure the yellow block is centered and flat on top of the wooden block before releasing the gripper to achieve a stable stack.
  Summary: center yellow block; release stably
- **justification:** None