signal send_msg(msg)
#WE ARE IN THE BLUE SPRITES SCRIPT
func _ready():
var Red_sprite = get_parent().get_child(2)
self.connect("send_msg", Red_sprite,"recieve_message")
#redsprite has this function
#func recieve_message(msg):
#$Label.set_text("I got a msg it says: " + msg)
func _on_Button_pressed():
emit_signal("send_msg","from blue")
...
https://www.youtube.com/watch?v=D3n9miDH_ZE