# t000__ep017__blocks

- **suite / variant:** `` / ``
- **instruction:** Stack the yellow block on the wooden block
- **success:** False
- **control steps:** 475  (9.5s at 50 Hz)
- **policy inferences:** 82  (replan_steps=6)
- **video:** `blocks/ep017/rollout.mp4`
- **features:** `82` prefix tensors (`prefix`; model=``)

## Semantic timeline

| seconds | control_step | policy_step | phrase |
|---|---|---|---|
| 0.0–3.0 | 0–150 | 0–25 | reaching for yellow block |
| 3.0–6.0 | 151–301 | 25–50 | grasping and placing yellow block |
| 6.0–9.0 | 302–452 | 50–75 | hovering above wooden block |
| 9.0–9.5 | 453–474 | 75–79 | idle near wooden block |

## Failure

- **yes**
- **onset type:** obvious_mistake
- **onset:** 5.199203187250996 s (00:05.2)
- **frame / control_step:** 261 (policy_step=43, chunk_index=3)
- **coarse onset:** 5.2 s (refined=False)
- **mode:** placement_or_insertion_failure
- **reason:** The robot successfully picked up the yellow block and moved it over the wooden block, but released it off-center, causing the yellow block to slide off and fall behind the wooden block.
  Summary: improper block placement; yellow block fell off wooden block
- **recovery:** Regrasp the fallen yellow block from the table, position it directly over the center of the wooden block, and place it carefully to stack it.
  Summary: regrasp yellow block; stack onto wooden block
- **prevention:** Align the yellow block directly over the center of the wooden block before releasing the gripper to ensure a stable stack.
  Summary: align yellow block centered; place stably on wooden block
- **justification:** At around 5.2 seconds (frame 00:05 to 00:06), the robot attempts to place the yellow block on the wooden block, but misaligns the placement, causing the yellow block to fall off and fail the goal predicate.