enum class Color {
    WHITE, BLACK,YELLOW
}

fun getAllVariants(sizeOfArray: Int): List<List<Color>> {
    if (sizeOfArray <= 0) return emptyList()

    var list = emptyList<List<Color>>()
    for (i in 0 until sizeOfArray) {
        list = mixWith(list)
    }
    return list
}

fun mixWith(variants: List<List<Color>>): List<List<Color>> {
    //variants for size of 1
    if (variants.isEmpty()) {
        val result = mutableListOf<List<Color>>()
        for (color in Color.values()) {
            result.add(listOf(color))
        }
        return result
    }
    return variants
        .flatMap { variant ->
            //making more variants by adding one more color to each list
            val result = mutableListOf<List<Color>>()
            for (color in Color.values()) {
                result.add(variant + color)
            }
            result
        }
}

print(getAllVariants(2))