Generating Downhill Terrain

[Denis-Memo]

Hellow, Is there any way i can generate downhills slopes? I played with your code a lot and i was only able to create uphills terrain, it seems changing number_hills to 1 and dividing j by 2 in hill_point.y gives you an uphills terrain. I would like downhills slopes but am unable to generate

Here are the code:

Terrain.gd

extends Node

export var num_hills = 1
export var slice = 10
export var hill_range = 100

var screensize
var terrain = Array()
var texture = preload("res://grass.png")

func _ready():
	randomize()
	screensize = get_viewport().get_visible_rect().size
	terrain = Array()
	var start_y = screensize.y * 3/4 + (-hill_range + randi() % hill_range*2)
	terrain.append(Vector2(0, start_y))
	add_hills()
	
func _process(delta):
	if terrain[-1].x < $Runner.position.x + screensize.x / 2:
		add_hills()
	
func add_hills():
	var hill_width = screensize.x / num_hills
	var hill_slices = hill_width / slice
	var start = terrain[-1]
	var poly = PoolVector2Array()
	for i in range(num_hills):
		var height = randi() % hill_range
		start.y -= height
		for j in range(0, hill_slices):
			var hill_point = Vector2()
			hill_point.x = start.x + j * slice + hill_width * i
			hill_point.y = start.y + height * cos(2 * PI / hill_slices * j/2)
			#$Line2D.add_point(hill_point)
			terrain.append(hill_point)
			poly.append(hill_point)
		start.y += height
	var shape = CollisionPolygon2D.new()
	var ground = Polygon2D.new()
	$StaticBody2D.add_child(shape)
	poly.append(Vector2(terrain[-1].x, screensize.y))
	poly.append(Vector2(start.x, screensize.y))
	shape.polygon = poly
	ground.polygon = poly
	ground.texture = texture
	add_child(ground)