diff --git a/TODO.md b/TODO.md
index 2ae9de9..2e877bf 100644
--- a/TODO.md
+++ b/TODO.md
@@ -3,4 +3,12 @@
 2. Proper support for dynamic chart display size.
 3. Fix (very rare) crashes in parsing strings (`TextDecoder.decode: Decoding failed.`)
 4. Multiple functions in one graph.
+    - Backend support
+        - Generation of data
+        - Management
+            - Handle by IDs
+    - UI
+        - Dynamically create inputs
+        - Different colors
+        - Better Handling of area and integrals
 5. Non `y=` functions.
\ No newline at end of file
diff --git a/src/chart_manager.rs b/src/chart_manager.rs
deleted file mode 100644
index a22595c..0000000
--- a/src/chart_manager.rs
+++ /dev/null
@@ -1,130 +0,0 @@
-use crate::misc::{add_asterisks, Function};
-
-pub enum UpdateType {
-    Full,
-    Front,
-    Back,
-    None,
-}
-
-// Manages Chart generation and caching of values
-pub struct ChartManager {
-    function: Function,
-    min_x: f64,
-    max_x: f64,
-    min_x_back: f64,
-    max_x_back: f64,
-    num_interval: usize,
-    resolution: usize,
-}
-
-impl ChartManager {
-    pub fn new(
-        func_str: String, min_x: f64, max_x: f64, min_x_back: f64, max_x_back: f64,
-        num_interval: usize, resolution: usize,
-    ) -> Self {
-        Self {
-            function: Function::from_string(func_str),
-            min_x,
-            max_x,
-            min_x_back,
-            max_x_back,
-            num_interval,
-            resolution,
-        }
-    }
-
-    #[inline]
-    pub fn draw_back(&mut self) -> Vec<(f64, f64)> {
-        let absrange = (self.max_x_back - self.min_x_back).abs();
-        let output: Vec<(f64, f64)> = (1..=self.resolution)
-            .map(|x| ((x as f64 / self.resolution as f64) * absrange) + self.min_x_back)
-            .map(|x| (x, self.function.run(x)))
-            .collect();
-        output
-    }
-
-    #[inline]
-    pub fn draw_front(&mut self) -> (Vec<(f64, f64)>, f64) {
-        self.integral_rectangles(self.get_step())
-    }
-
-    #[inline]
-    pub fn get_step(&self) -> f64 { (self.max_x - self.min_x).abs() / (self.num_interval as f64) }
-
-    #[allow(clippy::too_many_arguments)]
-    pub fn update(
-        &mut self, func_str_new: String, min_x: f64, max_x: f64, min_x_back: f64, max_x_back: f64,
-        num_interval: usize, resolution: usize,
-    ) -> UpdateType {
-        let func_str: String = add_asterisks(func_str_new);
-        let update_func: bool = !self.function.str_compare(func_str.clone());
-
-        let update_back =
-            update_func | (min_x_back != self.min_x_back) | (max_x_back != self.max_x_back);
-        let update_front = update_func
-            | (min_x != self.min_x)
-            | (max_x != self.max_x)
-            | (self.resolution != resolution)
-            | (num_interval != self.num_interval);
-
-        if update_func {
-            self.function = Function::from_string(func_str);
-        }
-
-        self.min_x = min_x;
-        self.max_x = max_x;
-        self.min_x_back = min_x_back;
-        self.max_x_back = max_x_back;
-        self.num_interval = num_interval;
-        self.resolution = resolution;
-
-        if update_back && update_front {
-            UpdateType::Full
-        } else if update_back {
-            UpdateType::Back
-        } else if update_front {
-            UpdateType::Front
-        } else {
-            UpdateType::None
-        }
-    }
-
-    // Creates and does the math for creating all the rectangles under the graph
-    #[inline]
-    fn integral_rectangles(&self, step: f64) -> (Vec<(f64, f64)>, f64) {
-        let half_step = step / 2.0;
-        let data2: Vec<(f64, f64)> = (0..self.num_interval)
-            .map(|e| {
-                let x: f64 = ((e as f64) * step) + self.min_x;
-
-                // Makes sure rectangles are properly handled on x values below 0
-                let x2: f64 = match x > 0.0 {
-                    true => x + step,
-                    false => x - step,
-                };
-
-                let tmp1: f64 = self.function.run_func(x);
-                let tmp2: f64 = self.function.run_func(x2);
-
-                // Chooses the y value who's absolute value is the smallest
-                let mut output = match tmp2.abs() > tmp1.abs() {
-                    true => (x, tmp1),
-                    false => (x2, tmp2),
-                };
-
-                // Applies `half_step` in order to make the bar graph display properly
-                if output.0 > 0.0 {
-                    output.0 += half_step;
-                } else {
-                    output.0 -= half_step;
-                }
-
-                output
-            })
-            .filter(|(_, y)| !y.is_nan())
-            .collect();
-        let area: f64 = data2.iter().map(|(_, y)| y * step).sum(); // sum of all rectangles' areas
-        (data2, area)
-    }
-}
diff --git a/src/egui_app.rs b/src/egui_app.rs
index 969a807..05e9a5c 100644
--- a/src/egui_app.rs
+++ b/src/egui_app.rs
@@ -1,7 +1,7 @@
 use std::ops::RangeInclusive;
 
-use crate::chart_manager::{ChartManager, UpdateType};
-use crate::misc::{digits_precision, test_func, Cache};
+use crate::function::Function;
+use crate::misc::{digits_precision, test_func};
 use eframe::{egui, epi};
 use egui::plot::{Line, Plot, Value, Values};
 use egui::widgets::plot::{Bar, BarChart};
@@ -12,98 +12,60 @@ use git_version::git_version;
 const GIT_VERSION: &str = git_version!();
 
 // Sets some hard-coded limits to the application
-const NUM_INTERVAL_RANGE: RangeInclusive<usize> = 10..=1000000;
+const INTEGRAL_NUM_RANGE: RangeInclusive<usize> = 10..=1000000;
 const MIN_X_TOTAL: f64 = -1000.0;
 const MAX_X_TOTAL: f64 = 1000.0;
 const X_RANGE: RangeInclusive<f64> = MIN_X_TOTAL..=MAX_X_TOTAL;
 
 pub struct MathApp {
-    func_str: String,
+    functions: Vec<Function>,
     min_x: f64,
     max_x: f64,
 
     // Currently really unused. But once fully implemented it will represent the full graph's min_x and max_x, being seperate from min_x and max_x for the intergral.
-    min_x_graph: f64,
-    max_x_graph: f64,
+    integral_min_x: f64,
+    integral_max_x: f64,
 
-    num_interval: usize,
-    resolution: usize,
-    chart_manager: ChartManager,
-    back_cache: Cache<Vec<Value>>,
-    front_cache: Cache<(Vec<Bar>, f64)>,
+    integral_num: usize,
 }
 
 impl Default for MathApp {
     #[inline]
     fn default() -> Self {
-        let def_func = "x^2".to_string();
+        let def_func_str = "x^2".to_string();
         let def_min_x = -10.0;
         let def_max_x = 10.0;
         let def_interval: usize = 1000;
-        let def_resolution: usize = 10000;
+
+        let def_funcs: Vec<Function> = vec![Function::new(
+            def_func_str,
+            def_min_x,
+            def_max_x,
+            true,
+            Some(def_min_x),
+            Some(def_max_x),
+            Some(def_interval),
+        )];
 
         Self {
-            func_str: def_func.clone(),
+            functions: def_funcs,
             min_x: def_min_x,
             max_x: def_max_x,
-            min_x_graph: def_min_x,
-            max_x_graph: def_max_x,
-            num_interval: def_interval,
-            resolution: def_resolution,
-            chart_manager: ChartManager::new(
-                def_func,
-                def_min_x,
-                def_max_x,
-                def_min_x,
-                def_max_x,
-                def_interval,
-                def_resolution,
-            ),
-            back_cache: Cache::new_empty(),
-            front_cache: Cache::new_empty(),
+            integral_min_x: def_min_x,
+            integral_max_x: def_max_x,
+            integral_num: def_interval,
         }
     }
 }
 
 impl MathApp {
     #[inline]
-    fn get_back(&mut self) -> Line {
-        let data = if self.back_cache.is_valid() {
-            self.back_cache.get().clone()
-        } else {
-            let data = self.chart_manager.draw_back();
-            let data_values: Vec<Value> = data.iter().map(|(x, y)| Value::new(*x, *y)).collect();
-            self.back_cache.set(data_values.clone());
-            data_values
-        };
-        Line::new(Values::from_values(data)).color(Color32::RED)
-    }
-
-    #[inline]
-    fn get_front(&mut self) -> (Vec<Bar>, f64) {
-        if self.front_cache.is_valid() {
-            let cache = self.front_cache.get();
-            let vec_bars: Vec<Bar> = cache.0.to_vec();
-            (vec_bars, cache.1)
-        } else {
-            let (data, area) = self.chart_manager.draw_front();
-            let bars: Vec<Bar> = data.iter().map(|(x, y)| Bar::new(*x, *y)).collect();
-
-            let output = (bars, area);
-            self.front_cache.set(output.clone());
-            output
-        }
-    }
-
-    #[inline]
-    fn get_data(&mut self) -> (Line, Vec<Bar>, f64) {
-        let (bars, area) = self.get_front();
-        (self.get_back(), bars, area)
+    pub fn get_step(&self) -> f64 {
+        (self.integral_min_x - self.integral_max_x).abs() / (self.integral_num as f64)
     }
 }
 
 impl epi::App for MathApp {
-    
     // The name of the program (displayed when running natively as the window title)
     fn name(&self) -> &str { "Integral Demonstration" }
 
@@ -118,16 +80,12 @@ impl epi::App for MathApp {
     #[inline]
     fn update(&mut self, ctx: &egui::Context, _frame: &epi::Frame) {
         let Self {
-            func_str,
+            functions,
             min_x,
             max_x,
-            min_x_graph,
-            max_x_graph,
-            num_interval,
-            resolution,
-            chart_manager,
-            back_cache,
-            front_cache,
+            integral_min_x,
+            integral_max_x,
+            integral_num,
         } = self;
 
         // Note: This Instant implementation does not show microseconds when using wasm.
@@ -146,21 +104,28 @@ impl epi::App for MathApp {
                 ui.label("- signum, min, max");
             });
 
+        let mut func_new_strings: Vec<String> = Vec::new();
         let mut parse_error: String = "".to_string();
         egui::SidePanel::left("side_panel")
             .resizable(false)
             .show(ctx, |ui| {
                 ui.heading("Side Panel");
 
-                ui.horizontal(|ui| {
-                    ui.label("Function: ");
-                    ui.text_edit_singleline(func_str);
-                });
+                for function in functions.iter() {
+                    let mut func_str = function.get_string();
+                    ui.horizontal(|ui| {
+                        ui.label("Function: ");
+                        ui.text_edit_singleline(&mut func_str);
+                    });
 
-                let func_test_output = test_func(func_str.clone());
-                if !func_test_output.is_empty() {
-                    parse_error = func_test_output;
+                    let func_test_output = test_func(func_str.clone());
+                    if !func_test_output.is_empty() {
+                        parse_error += &func_test_output;
+                    }
+
+                    func_new_strings.push(func_str);
                 }
+
                 let min_x_old = *min_x;
                 let min_x_response =
                     ui.add(egui::Slider::new(min_x, X_RANGE.clone()).text("Min X"));
@@ -178,11 +143,11 @@ impl epi::App for MathApp {
                         *min_x = -10.0;
                         *max_x = 10.0;
                     }
-                    *min_x_graph = *min_x;
-                    *max_x_graph = *max_x;
+                    *integral_min_x = *min_x;
+                    *integral_max_x = *max_x;
                 }
 
-                ui.add(egui::Slider::new(num_interval, NUM_INTERVAL_RANGE).text("Interval"));
+                ui.add(egui::Slider::new(integral_num, INTEGRAL_NUM_RANGE).text("Interval"));
 
                 // Opensource and Licensing information
                 ui.horizontal(|ui| {
@@ -210,30 +175,13 @@ impl epi::App for MathApp {
                         ui.label(GIT_VERSION);
                     }
                 });
-            });
 
-        if parse_error.is_empty() {
-            let do_update = chart_manager.update(
-                func_str.clone(),
-                *min_x,
-                *max_x,
-                *min_x_graph,
-                *max_x_graph,
-                *num_interval,
-                *resolution,
-            );
-
-            // Invalidates caches according to what settings were changed
-            match do_update {
-                UpdateType::Full => {
-                    back_cache.invalidate();
-                    front_cache.invalidate();
+                let mut i: usize = 0;
+                for function in functions.iter_mut() {
+                    function.update(func_new_strings[i].clone(), *min_x, *max_x, true, Some(*integral_min_x), Some(*integral_max_x), Some(*integral_num));
+                    i += 1;
                 }
-                UpdateType::Back => back_cache.invalidate(),
-                UpdateType::Front => front_cache.invalidate(),
-                _ => {}
-            }
-        }
+            });
 
         egui::CentralPanel::default().show(ctx, |ui| {
             if !parse_error.is_empty() {
@@ -241,26 +189,33 @@ impl epi::App for MathApp {
                 return;
             }
 
-            let (curve, bars, area) = self.get_data();
-
-            let bar_chart = BarChart::new(bars)
-                .color(Color32::BLUE)
-                .width(self.chart_manager.get_step());
-
+            let step = self.get_step();
+            let mut area_list: Vec<f64> = Vec::new();
             Plot::new("plot")
                 .view_aspect(1.0)
                 .data_aspect(1.0)
                 .include_y(0)
                 .show(ui, |plot_ui| {
-                    plot_ui.line(curve);
-                    plot_ui.bar_chart(bar_chart);
+                    for function in self.functions.iter_mut() {
+                        let output = function.run();
+                        let back = output.get_back();
+                        plot_ui.line(Line::new(Values::from_values(back)).color(Color32::RED));
+
+                        if output.has_integral() {
+                            let (bars, area) = output.get_front();
+                            let bar_chart =
+                                BarChart::new(bars.clone()).color(Color32::BLUE).width(step);
+                            plot_ui.bar_chart(bar_chart);
+                            area_list.push(digits_precision(area, 8))
+                        }
+                    }
                 });
 
             let duration = start.elapsed();
 
             ui.label(format!(
-                "Area: {} Took: {:?}",
-                digits_precision(area, 8),
+                "Area: {:?} Took: {:?}",
+                area_list.clone(),
                 duration
             ));
         });
diff --git a/src/function.rs b/src/function.rs
index 09cfc25..15ade42 100644
--- a/src/function.rs
+++ b/src/function.rs
@@ -1,9 +1,9 @@
-use meval::Expr;
+use crate::misc::Cache;
 use egui::plot::Value;
 use egui::widgets::plot::Bar;
+use meval::Expr;
 
-const RESOLUTION: f64 = 1000.0;
-
+pub const RESOLUTION: f64 = 1000.0;
 
 // Struct that stores and manages the output of a function
 pub struct FunctionOutput {
@@ -16,16 +16,22 @@ pub struct FunctionOutput {
 
 impl FunctionOutput {
     #[inline]
-    pub fn new(back: Vec<Value>, front: Option<(Vec<Bar>, f64)>) -> Self {
-        Self {
-            back,
-            front,
+    pub fn new(back: Vec<Value>, front: Option<(Vec<Bar>, f64)>) -> Self { Self { back, front } }
+
+    #[inline]
+    pub fn get_back(&self) -> Vec<Value> { self.back.clone() }
+
+    #[inline]
+    pub fn get_front(&self) -> (Vec<Bar>, f64) {
+        match &self.front {
+            Some(x) => (x.0.clone(), x.1.clone()),
+            None => panic!(""),
         }
     }
 
     #[inline]
-    fn has_integral(&self) -> bool {
-        match self.front {
+    pub fn has_integral(&self) -> bool {
+        match &self.front {
             Some(x) => true,
             None => false,
         }
@@ -37,6 +43,7 @@ pub struct Function {
     func_str: String,
     min_x: f64,
     max_x: f64,
+
     back_cache: Cache<Vec<Value>>,
     front_cache: Cache<(Vec<Bar>, f64)>,
 
@@ -47,8 +54,10 @@ pub struct Function {
 }
 
 impl Function {
-    pub fn new(func_str: String, min_x: f64, max_x: f64, integral: bool, integral_min_x: Option<f64>, integral_max_x: Option<f64>, integral_num: Option<usize>) -> Self {
-
+    pub fn new(
+        func_str: String, min_x: f64, max_x: f64, integral: bool, integral_min_x: Option<f64>,
+        integral_max_x: Option<f64>, integral_num: Option<usize>,
+    ) -> Self {
         // Makes sure proper arguments are passed when integral is enabled
         if integral {
             if integral_min_x.is_none() {
@@ -80,7 +89,7 @@ impl Function {
             },
             integral_num: match integral_num {
                 Some(x) => x,
-                None => f64::NAN,
+                None => 0,
             },
         }
     }
@@ -90,15 +99,24 @@ impl Function {
     fn run_func(&self, x: f64) -> f64 { (self.function)(x) }
 
     #[inline]
-    pub fn update(&mut self, func_str: String, min_x: f64, max_x: f64, integral: bool, integral_min_x: Option<f64>, integral_max_x: Option<f64>, integral_num: Option<usize>) {
-
+    pub fn update(
+        &mut self, func_str: String, min_x: f64, max_x: f64, integral: bool,
+        integral_min_x: Option<f64>, integral_max_x: Option<f64>, integral_num: Option<usize>,
+    ) {
         // If the function string changes, just wipe and restart from scratch
         if func_str != self.func_str {
-            *self = Self::new(func_str, min_x, max_x, integral, integral_min_x, integral_max_x, integral_num);
+            *self = Self::new(
+                func_str,
+                min_x,
+                max_x,
+                integral,
+                integral_min_x,
+                integral_max_x,
+                integral_num,
+            );
             return;
         }
 
-
         if (min_x != self.min_x) | (max_x != self.max_x) {
             self.back_cache.invalidate();
             self.min_x = min_x;
@@ -115,38 +133,81 @@ impl Function {
                 panic!("Invalid arguments: integral_num is None, but integral is enabled.")
             }
 
-            if (integral_min_x != Some(self.integral_min_x)) | (integral_max_x != Some(self.integral_max_x)) | (integral_num != Some(self.integral_num)) {
+            if (integral_min_x != Some(self.integral_min_x))
+                | (integral_max_x != Some(self.integral_max_x))
+                | (integral_num != Some(self.integral_num))
+            {
                 self.front_cache.invalidate();
                 self.integral_min_x = integral_min_x.expect("");
                 self.integral_max_x = integral_max_x.expect("");
                 self.integral_num = integral_num.expect("");
             }
         }
-
     }
 
+    #[inline]
+    pub fn get_step(&self) -> f64 {
+        (self.integral_min_x - self.integral_max_x).abs() / (self.integral_num as f64)
+    }
+
+    #[inline]
+    pub fn is_integral(&self) -> bool { self.integral }
 
     #[inline]
     pub fn run(&mut self) -> FunctionOutput {
-        let absrange = (self.max_x - self.min_x).abs();
-        let output: Vec<(f64, f64)> = (1..=self.resolution)
-            .map(|x| ((x as f64 / RESOLUTION) * absrange) + self.min_x_back)
-            .map(|x| (x, self.function.run(x)))
-            .collect();
-        output
+        let front_values: Vec<Value> = match self.back_cache.is_valid() {
+            false => {
+                let absrange = (self.max_x - self.min_x).abs();
+                let front_data: Vec<(f64, f64)> = (1..=(RESOLUTION as usize))
+                    .map(|x| ((x as f64 / RESOLUTION) * absrange) + self.min_x)
+                    .map(|x| (x, self.run_func(x)))
+                    .collect();
+                let output: Vec<Value> =
+                    front_data.iter().map(|(x, y)| Value::new(*x, *y)).collect();
+                self.back_cache.set(output.clone());
+                output
+            }
+            true => self.back_cache.get().clone(),
+        };
+
+        if self.integral {
+            let back_bars: (Vec<Bar>, f64) = match self.front_cache.is_valid() {
+                false => {
+                    let (data, area) = self.integral_rectangles();
+                    let bars: Vec<Bar> = data.iter().map(|(x, y)| Bar::new(*x, *y)).collect();
+
+                    let output = (bars, area);
+                    self.front_cache.set(output.clone());
+                    output
+                }
+                true => {
+                    let cache = self.front_cache.get();
+                    let vec_bars: Vec<Bar> = cache.0.to_vec();
+                    (vec_bars, cache.1)
+                }
+            };
+            FunctionOutput::new(front_values, Some(back_bars))
+        } else {
+            FunctionOutput::new(front_values, None)
+        }
     }
 
+    #[inline]
+    pub fn get_string(&self) -> String { self.func_str.clone() }
+
     #[inline]
     pub fn str_compare(&self, other_string: String) -> bool { self.func_str == other_string }
 
-    #[inline]
-    pub fn get_step(&self) -> f64 { (self.integral_min_x - self.integral_max_x).abs() / (self.num_interval as f64) }
-
     // Creates and does the math for creating all the rectangles under the graph
     #[inline]
-    fn integral_rectangles(&self, step: f64) -> (Vec<(f64, f64)>, f64) {
+    fn integral_rectangles(&self) -> (Vec<(f64, f64)>, f64) {
+        if !self.integral {
+            panic!("integral_rectangles called, but self.integral is false!");
+        }
+        let step = self.get_step();
+
         let half_step = step / 2.0;
-        let data2: Vec<(f64, f64)> = (0..self.num_interval)
+        let data2: Vec<(f64, f64)> = (0..self.integral_num)
             .map(|e| {
                 let x: f64 = ((e as f64) * step) + self.integral_min_x;
 
@@ -179,4 +240,4 @@ impl Function {
         let area: f64 = data2.iter().map(|(_, y)| y * step).sum(); // sum of all rectangles' areas
         (data2, area)
     }
-}
\ No newline at end of file
+}
diff --git a/src/lib.rs b/src/lib.rs
index 0fe484c..28fae50 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,10 +1,9 @@
 #![allow(clippy::unused_unit)] // Fixes clippy keep complaining about wasm_bindgen
 #![allow(clippy::type_complexity)] // Clippy, my types are fine.
 
-mod chart_manager;
 mod egui_app;
-mod misc;
 mod function;
+mod misc;
 
 #[cfg(target_arch = "wasm32")]
 use wasm_bindgen::prelude::*;
diff --git a/src/main.rs b/src/main.rs
index 653586c..a8f225f 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,9 +1,7 @@
 mod egui_app;
 
-// These 2 are needed for rust-analyzer to work in vscode.
-mod chart_manager;
-mod misc;
 mod function;
+mod misc;
 
 // For running the program natively! (Because why not?)
 #[cfg(not(target_arch = "wasm32"))]