Function classifyQuad

classifyQuad(x: ParetoClass, y: ParetoClass): Quad
Determines the Quad for a point from its X and Y Pareto classes.
Parameters
- x: ParetoClass
  The X-axis Pareto class.
- y: ParetoClass
  The Y-axis Pareto class.
Returns Quad
The quadrant 1–4.
Example
```
classifyQuad('vital', 'vital');     // 1
classifyQuad('vital', 'trivial');   // 2
classifyQuad('trivial', 'vital');   // 3
classifyQuad('trivial', 'trivial'); // 4
```
- Defined in quad/index.ts:41