
Original Concept:
```yaml
diagonal line drawing:
    Kind: grid manipulation
    Routine Subtype: N/A
    Output Typing: grid | list[coord]
    Parameters:
    - name: start_point
      typing: coord
      description: anchor A
    - name: end_point
      typing: coord
      description: anchor B
    - name: stop_condition
      typing: Literal['same-row','same-col']
      description: termination criterion for the diagonal
    - name: path_colour
      typing: color
      description: '3'
    Description: From the first anchor draw a checker‑board diagonal (colour 3) toward
      the second anchor until either the same row OR column is reached.
    Implementation:
    - Walk stepwise with (dr,dc) in {(+1,+1),(+1,−1)} choosing the variant heading toward the end; colour every step; stop when stop_condition is met.
    Cues:
    - Output shows a 45° staircase path of colour 3 linking toward the opposite anchor.
```

Converted Description:
```python
# concepts: diagonal staircase path, stepwise walk, termination on alignment
# description: Given two anchor pixels A and B, paint a 1-pixel-wide staircase path starting at A with steps (±1, +1) chosen to greedily reduce |row−row_B| and |col−col_B| each step. Color each visited cell with path_colour=3. Stop immediately when either A’s current row equals B’s row (same-row) or A’s current column equals B’s column (same-col), according to the provided stop_condition. Do not paint beyond alignment; leave all other cells unchanged.
```
