# t000__ep015__blocks

- **suite / variant:** `` / ``
- **instruction:** Stack the yellow block on the wooden block
- **success:** False
- **control steps:** 1080  (21.3s at 51 Hz)
- **policy inferences:** 185  (replan_steps=6)
- **video:** `blocks/ep015/rollout.mp4`
- **features:** `185` prefix tensors (`prefix`; model=``)

## Semantic timeline

| seconds | control_step | policy_step | phrase |
|---|---|---|---|
| 0.0–3.0 | 0–151 | 0–25 | approaching yellow block |
| 3.0–6.0 | 152–303 | 25–50 | grasping yellow block |
| 6.0–9.0 | 304–455 | 50–75 | carrying yellow block to target |
| 9.0–12.0 | 456–607 | 76–101 | releasing yellow block off-center |
| 12.0–15.0 | 608–759 | 101–126 | pushing yellow block aside |
| 15.0–18.0 | 760–911 | 126–151 | dragging yellow block |
| 18.0–21.0 | 912–1063 | 152–177 | hovering near yellow block |
| 21.0–21.3 | 1064–1079 | 177–179 | idle near yellow block |

## Failure

- **yes**
- **onset type:** obvious_mistake
- **onset:** 9.703557312252965 s (00:09.7)
- **frame / control_step:** 491 (policy_step=81, chunk_index=5)
- **coarse onset:** 9.5 s (refined=True)
- **mode:** placement_or_insertion_failure
- **reason:** The robot misaligned the yellow block while attempting to stack it, causing the block to hit the edge of the wooden block and slide off onto the tabletop.
  Summary: misaligned block placement; sliding off target block
- **recovery:** Re-grasp the yellow block, align it directly above the center of the wooden block, and lower it gently onto the top surface.
  Summary: re-grasp yellow block; stack cleanly on wooden block
- **prevention:** Ensure the robot aligns the yellow block squarely over the center of the wooden block before opening the gripper to release it.
  Summary: center block over target; release gently
- **justification:** At around 9.5 seconds, the robot lowers the yellow block onto the edge of the wooden block instead of centering it. As the gripper opens, the yellow block slides off the wooden block and falls to the side, failing the goal to stack the yellow block on the wooden block.