- let leftRegion = { currentRegion with maxX = splitValue }
- let rightRegion = { currentRegion with minX = splitValue }
- (valuesInRegion leftRegion part1) @ (valuesInRegion rightRegion part2)
+ valuesInRegion { currentRegion with maxX = splitValue } part1 // Left region.
+ valuesInRegion { currentRegion with minX = splitValue } part2 // Right region.