diff --git a/src/formula/mod.rs b/src/formula/mod.rs
deleted file mode 100644
index b0d4024..0000000
--- a/src/formula/mod.rs
+++ /dev/null
@@ -1,18 +0,0 @@
-use crate::formula::node::Node;
-
-pub mod node;
-
-pub struct Formula {
-    root: node::Node,
-}
-
-impl Formula {
-    pub fn new(optional_root: Option<node::Node>) -> Self {
-        match optional_root {
-            Some(root) => Formula { root },
-            None => Formula {
-                root: node::Node::empty(),
-            },
-        }
-    }
-}
diff --git a/src/formula/node/graph_builder.rs b/src/formula/node/graph_builder.rs
deleted file mode 100644
index 7b6ac61..0000000
--- a/src/formula/node/graph_builder.rs
+++ /dev/null
@@ -1,24 +0,0 @@
-use crate::formula::node::Node;
-
-pub struct GraphBuilder(Node);
-
-impl GraphBuilder {
-    pub fn from_hash_maps(mut self) -> GraphBuilder {
-        self
-    }
-    /// Path format: /index0/index1/index2/.../indexn
-    /// For example: /0/1/0/0/1
-    /// The reason for unreadable format is because graph builder, as I ended up realising, doesn't need to be used.
-    pub fn add_at_path(mut self, path: String, func: fn(Vec<f64>) -> f64) -> GraphBuilder {
-        let mut node_lookup = self.0;
-        for i in path.split("/").map(str::parse::<i64>) {
-            if let Ok(index) = i {
-                node_lookup = node_lookup.children[index];
-            }
-        }
-        self
-    }
-    pub fn finish(self) -> Node {
-        self.0
-    }
-}
diff --git a/src/formula/node/graph_modifier.rs b/src/formula/node/graph_modifier.rs
deleted file mode 100644
index 4e779d7..0000000
--- a/src/formula/node/graph_modifier.rs
+++ /dev/null
@@ -1 +0,0 @@
-struct GraphModifier;
diff --git a/src/lib.rs b/src/lib.rs
index 746f792..274142d 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1 +1 @@
-mod formula;
+mod node;
diff --git a/src/node/graph_modifier.rs b/src/node/graph_modifier.rs
new file mode 100644
index 0000000..df429e4
--- /dev/null
+++ b/src/node/graph_modifier.rs
@@ -0,0 +1,12 @@
+use crate::node::Node;
+
+pub struct GraphModifier<'a> {
+    root: &'a Node,
+}
+
+impl<'a> GraphModifier<'a> {
+    pub fn new(root: &Node) -> GraphModifier {
+        GraphModifier { root }
+    }
+    
+}
diff --git a/src/formula/node/mod.rs b/src/node/mod.rs
similarity index 59%
rename from src/formula/node/mod.rs
rename to src/node/mod.rs
index 32a39bc..6aaa697 100644
--- a/src/formula/node/mod.rs
+++ b/src/node/mod.rs
@@ -1,6 +1,5 @@
-use crate::formula::node::graph_builder::GraphBuilder;
+use crate::node::graph_modifier::GraphModifier;
 
-mod graph_builder;
 mod graph_modifier;
 
 pub struct Node {
@@ -9,15 +8,18 @@ pub struct Node {
 }
 
 impl Node {
+    pub fn new(children: Option<Vec<Node>>, function: Option<fn(Vec<f64>) -> f64>) -> Self {
+        Self {
+            children: children.unwrap_or(vec![]),
+            function: function.unwrap_or(|_| 0f64),
+        }
+    }
     pub fn empty() -> Self {
-        Node {
+        Self {
             children: vec![],
             function: |_| 0f64,
         }
     }
-    pub fn build() -> GraphBuilder {
-        GraphBuilder
-    }
     pub fn get_value(&self) -> f64 {
         if self.children.len() == 0 {
             return (self.function)(vec![0f64]);
@@ -29,4 +31,7 @@ impl Node {
 
         return (self.function)(inputs);
     }
+    pub fn modify_tree(&self) -> GraphModifier {
+        GraphModifier::new(self)
+    }
 }