
Original Concept:
```yaml
d931c21c:
  border recolour (inside):
    Kind: grid manipulation
    Routine Subtype: N/A
    Output Typing: grid
    Parameters:
    - name: hole_colour
      typing: color
      description: colour of interior placeholder (4)
    - name: border_colour
      typing: color
      description: target colour to paint where touching blue (3)
    Description: Re‑colour every interior‑hole pixel (4) that shares an edge with
      a blue pixel (1) to green 3, leaving deeper interior 4's as‑is.
    Implementation:
    - Build mask of hole_colour cells that are 4‑adjacent to blue; paint those to border_colour; keep non‑adjacent hole cells unchanged.
    Cues:
    - Only the hole cells directly touching the blue frame change to green; deeper holes remain 4.
```

Converted Description:
```python
# concepts: adjacency (4-connectivity), holes, border tracing, recolor
# description: Input is a single object that forms a closed frame (blue=1) surrounding interior "hole" cells (4) on a background (0). Treat connectivity as 4-connected. Recolor precisely those 4-cells that share an edge with any blue=1 pixel to border_colour (green=3); leave all other 4-cells unchanged. All non-4 pixels are preserved. The result is that only the interior ring of 4 that touches the frame changes color; deeper 4-regions remain 4.
```