+/**
+ * roam_diamond_new:
+ * @parent0: a parent triangle
+ * @parent1: a parent triangle
+ * @kid0: a child triangle
+ * @kid1: a child triangle
+ * @kid2: a child triangle
+ * @kid3: a child triangle
+ *
+ * Create a diamond to store information about two split triangles.
+ *
+ * Returns: the new diamond
+ */