Collektive

fun Aggregate<Int>.neighborCounter(): Int =
    neighboring(1).hood(0) { acc, _ ->
        acc + 1
    }

context(Aggregate<Int>, DistanceSensor)
fun gradient(source: Boolean): Double =
    share(POSITIVE_INFINITY) {
        val dist = distances()
        when {
            source -> 0.0
            else -> (it + dist).min(100)
        }
    }