Whisper
Neighbouring values along the line differ by at least the stated gap.
Parameters
| Parameter | Meaning | Default |
|---|---|---|
| line | The cells in order, for example r1c1-r1c2-r1c3. | Required. |
| gap | The least difference between neighbours: 5 for German whispers, 4 for Dutch whispers. | Required. |
| loop | Whether the line closes, joining its last cell back to its first. | false (open path). |
Maths
Class: first-order.
The shared predicates define the notation and every named predicate.
∀i,j∈[0,|line|): consecutive(line,i,j,loop) → |V(line[i])-V(line[j])|>=gap
Neighbouring path positions differ in value by at least gap. Include last/first when loop is true.
Example
---
format: open-rules
title: Whisper example
setter: Example
source: ""
case: ""
library: https://rules.sudoku-sleuth.com/
status: read
---
```rules
sudoku 9x9
whispers r1c1-r1c2 gap 5
```
Satisfies the rule: r1c1=1, r1c2=6. 1 and 6 differ by 5.
Breaks the rule: r1c1=1, r1c2=5. 1 and 5 differ by only 4.