diff --git a/include/Particle.hpp b/include/Particle.hpp
new file mode 100644
index 0000000..29b4ccb
--- /dev/null
+++ b/include/Particle.hpp
@@ -0,0 +1,41 @@
+/** @file Particle.hpp
+ *
+ *  @author Cory Alexander Balaton (coryab)
+ *  @author Janita Ovidie Sandtrøen Willumsen (janitaws)
+ *
+ *  @version 0.1
+ *
+ *  @brief A class that holds the properties of a particle.
+ *
+ *  @bug No known bugs
+ * */
+#ifndef __PARTICLE__
+#define __PARTICLE__
+
+#include <armadillo>
+
+/** @brief A class that holds attributes of a particle
+ * */
+class Particle {
+private:
+    double q; ///< Charge
+    double m; ///< Mass
+    arma::vec::fixed<3> r_vec; ///< position
+    arma::vec::fixed<3> v_vec; ///< velocity
+
+public:
+    /** @brief Initialize the particle.
+     *
+     *  @details Initialize the particle with a charge, mass, position and
+     *  velocity.
+     * */
+    Particle(double q, double m, 
+             arma::vec::fixed<3> r_vec, 
+             arma::vec::fixed<3> v_vec);
+
+    /** @brief Make private attributes available for PenningTrap.
+     * */
+    friend class PenningTrap;
+};
+
+#endif
diff --git a/include/PenningTrap.hpp b/include/PenningTrap.hpp
new file mode 100644
index 0000000..b0dbd86
--- /dev/null
+++ b/include/PenningTrap.hpp
@@ -0,0 +1,80 @@
+/** @file PenningTrap.hpp
+ *
+ *  @author Cory Alexander Balaton (coryab)
+ *  @author Janita Ovidie Sandtrøen Willumsen (janitaws)
+ *
+ *  @version 0.1
+ *
+ *  @brief A class for simulating a Penning trap.
+ *
+ *  @bug No known bugs
+ * */
+#ifndef __PENNING_TRAP__
+#define __PENNING_TRAP__
+
+#include <armadillo>
+
+#include "constants.hpp"
+#include "Particle.hpp"
+
+/** @brief A class that simulates a Penning trap.
+ *
+ *  This class simulates a Penning trap. It can take in a number of particles
+ *  and simulate how they would behave inside a Penning trap.
+ * */
+class PenningTrap {
+private:
+    double B_0; ///< Magnetic field strength
+    double V_0; ///< Applied potential
+    double d; ///< Characteristic dimension
+    std::vector<Particle> particles; ///< The particles in the Penning trap
+
+public:
+    /** @brief Set B_0, V_0 and d.
+     * */
+    PenningTrap(double B_0 = T, double V_0 = 25.*V/1000., double d = 500.);
+
+    /** @brief Add a particle to the system
+     * */
+    void add_particle(Particle particle);
+
+    /** @brief Calculate E at point r
+     * */
+    arma::vec external_E_field(arma::vec r);
+
+    /** @brief Calculate B at point r
+     * */
+    arma::vec external_B_field(arma::vec r);
+
+    /** @brief Calculate the force between 2 particles.
+     *
+     *  @details Calculate the force exhibited on particle p_i from 
+     *  particle p_j.
+     * */
+    arma::vec force_on_particle(int i, int j);
+
+    /** @brief Calculate the total external force on a particle.
+     *
+     *  @details Calculate the total amount of force that E and B exhibits
+     *  on particle p_i.
+     * */
+    arma::vec total_force_external(int i);
+
+    /** @brief Calculate the total force on a particle from other particles.
+     * */
+    arma::vec total_force_particles(int i);
+
+    /** @brief calculate the total force on a particle.
+     * */ 
+    arma::vec total_force(int i);
+
+    /** @brief Go forward one timestep using the RK4 method
+     * */
+    void evolve_RK4(double dt);
+
+    /** @brief Go forward one timestep using the forward Euler method
+     * */
+    void evolve_forward_euler(double dt);
+};
+
+#endif
diff --git a/include/constants.hpp b/include/constants.hpp
new file mode 100644
index 0000000..592b48a
--- /dev/null
+++ b/include/constants.hpp
@@ -0,0 +1,21 @@
+/** @file constants.hpp
+ *
+ *  @author Cory Alexander Balaton (coryab)
+ *  @author Janita Ovidie Sandtrøen Willumsen (janitaws)
+ *
+ *  @version 0.1
+ *
+ *  @brief Library of constants
+ *
+ *  @bug No known bugs
+ * */
+#ifndef __CONST__
+#define __CONST__
+
+#define K_E 138935.333 ///< Coulomb constant. unit: \f$\frac{u(\mu m)^3}{(\mu s)^2 e^2}\f$
+
+#define T 96.4852558 ///< 1 Tesla. unit: \f$ \frac{u}{(\mu s) e} \f$
+
+#define V 96485255.8 ///< 1 Volt. unit: \f$ \frac{u (\mu m)^2}{(\mu s)^2 e} \f$
+
+#endif
diff --git a/include/utils.hpp b/include/utils.hpp
new file mode 100644
index 0000000..c8d3e4a
--- /dev/null
+++ b/include/utils.hpp
@@ -0,0 +1,65 @@
+/** @file utils.hpp
+ *
+ *  @author Cory Alexander Balaton (coryab)
+ *  @author Janita Ovidie Sandtrøen Willumsen (janitaws)
+ *
+ *  @version 1.0
+ *
+ *  @brief Function prototypes and macros that are useful.
+ *
+ *  These utility function are mainly for convenience and aren't directly
+ *  related to the project.
+ *
+ *  @bug No known bugs
+ * */
+#ifndef __UTILS__
+#define __UTILS__
+
+#include <string>
+#include <vector>
+#include <iomanip>
+#include <sstream>
+
+/** @def DEBUG(msg)
+ *  @brief Writes a debug message
+ *
+ *  This function writes a debug message that includes the filename,
+ *  line number, and a custom message. The function is wrapped in an ifdef
+ *  that checks if DBG is defined, so one can choose to display the debug 
+ *  messages by adding the -DDBG flag when compiling.
+ * */
+#ifdef DBG
+    #define DEBUG(msg) std::cout << __FILE__ << " " << __LINE__ << ": " \
+        << msg << std::endl
+#else
+    #define DEBUG(msg)
+#endif
+
+/** Code stolen from https://github.com/anderkve/FYS3150
+ *  Header: https://github.com/anderkve/FYS3150/blob/master/code_examples/compilation_linking/example_1/include/utils.hpp
+ *  Source: https://github.com/anderkve/FYS3150/blob/master/code_examples/compilation_linking/example_1/src/utils.cpp
+ * */
+
+/** @brief Turns a double into a string written in scientific format.
+ *
+ *  @param d The number to stringify
+ *  @param width The reserved width of the string
+ *  @param prec The precision of the stringified number
+ *
+ *  @return String
+ * */
+std::string scientific_format(double d, int width=20, int prec=10);
+
+/** @brief Turns a vector of doubles into a string written in scientific format.
+ *
+ *  @param v The vector to stringify
+ *  @param width The reserved width of the string
+ *  @param prec The precision of the stringified number
+ *
+ *  @return String
+ * */
+std::string scientific_format(const std::vector<double>& v, 
+                              int width=20, 
+                              int prec=10);
+
+#endif
diff --git a/src/Makefile b/src/Makefile
new file mode 100644
index 0000000..fd101c7
--- /dev/null
+++ b/src/Makefile
@@ -0,0 +1,40 @@
+CC=g++
+
+LIBSRCS=utils.cpp
+LIBOBJS=$(LIBSRCS:.cpp=.o)
+
+CLASSSRCS=PenningTrap.cpp Particle.cpp
+CLASSOBJS=$(CLASSSRCS:.cpp=.o)
+
+INCLUDE=../include
+
+CFLAGS=-larmadillo -llapack -std=c++11
+OPENMP=-fopenmp
+
+# Add a debug flag when compiling (For the DEBUG macro in utils.hpp)
+DEBUG ?= 0
+ifeq ($(DEBUG), 1)
+	DBGFLAG=-DDBG
+else
+	DBGFLAG=
+endif
+
+.PHONY: clean
+
+all: test_suite main
+
+# Rules for executables
+main: main.o $(LIBOBJS)
+	$(CC) $^ -o $@ $(CFLAGS) $(DBGFLAG) -I$(INCLUDE) $(OPENMP)
+
+test_suite: test_suite.o $(LIBOBJS)
+	$(CC) $^ -o $@ $(CFLAGS) $(DBGFLAG) -I$(INCLUDE) $(OPENMP)
+
+# Rule for object files
+%.o: %.cpp
+	$(CC) -c $^ -o $@ $(DBGFLAG) -I$(INCLUDE) $(OPENMP)
+
+clean:
+	rm *.o
+	rm test_suite
+	rm main 
diff --git a/src/Particle.cpp b/src/Particle.cpp
new file mode 100644
index 0000000..1bcdb15
--- /dev/null
+++ b/src/Particle.cpp
@@ -0,0 +1,22 @@
+/** @file Particle.cpp
+ *
+ *  @author Cory Alexander Balaton (coryab)
+ *  @author Janita Ovidie Sandtrøen Willumsen (janitaws)
+ *
+ *  @version 0.1
+ *
+ *  @brief The implementation of the Particle class.
+ *
+ *  @bug No known bugs
+ *
+ *  @todo Implement constructor
+ * */
+
+#include "Particle.hpp"
+
+Particle::Particle(double q, double m,
+                   arma::vec::fixed<3> r_vec,
+                   arma::vec::fixed<3> v_vec)
+{
+
+}
diff --git a/src/PenningTrap.cpp b/src/PenningTrap.cpp
new file mode 100644
index 0000000..7a4ff2b
--- /dev/null
+++ b/src/PenningTrap.cpp
@@ -0,0 +1,74 @@
+/** @file PenningTrap.cpp
+ *
+ *  @author Cory Alexander Balaton (coryab)
+ *  @author Janita Ovidie Sandtrøen Willumsen (janitaws)
+ *
+ *  @version 0.1
+ *
+ *  @brief The implementation of the PenningTrap class.
+ *
+ *  @bug No known bugs
+ *
+ *  @todo Implement constructor
+ *  @todo Implement add_particle
+ *  @todo Implement external_E_field
+ *  @todo Implement external_B_field
+ *  @todo Implement force_on_particle
+ *  @todo Implement total_force_external
+ *  @todo Implement total_force_particles
+ *  @todo Implement total_force
+ *  @todo Implement evolve_RK4
+ *  @todo Implement evolve_forward_euler
+ * */
+
+#include "PenningTrap.hpp"
+
+PenningTrap::PenningTrap(double B_0, double V_0, double d)
+{
+
+}
+
+void PenningTrap::add_particle(Particle particle)
+{
+
+}
+
+arma::vec PenningTrap::external_E_field(arma::vec r)
+{
+
+}
+
+arma::vec PenningTrap::external_B_field(arma::vec r)
+{
+
+}
+
+arma::vec PenningTrap::force_on_particle(int i, int j)
+{
+
+}
+
+arma::vec PenningTrap::total_force_external(int i)
+{
+
+}
+
+arma::vec PenningTrap::total_force_particles(int i)
+{
+
+}
+
+arma::vec PenningTrap::total_force(int i)
+{
+
+}
+
+void PenningTrap::evolve_RK4(double dt)
+{
+
+}
+
+void PenningTrap::evolve_forward_euler(double dt)
+{
+
+}
diff --git a/src/main.cpp b/src/main.cpp
new file mode 100644
index 0000000..4c46902
--- /dev/null
+++ b/src/main.cpp
@@ -0,0 +1,16 @@
+/** @file main.cpp
+ *
+ *  @author Cory Alexander Balaton (coryab)
+ *  @author Janita Ovidie Sandtrøen Willumsen (janitaws)
+ *
+ *  @version 0.1
+ *
+ *  @brief The main program for this project
+ *
+ *  @bug No known bugs
+ * */
+
+int main() 
+{
+    return 0;
+}
diff --git a/src/test_suite.cpp b/src/test_suite.cpp
new file mode 100644
index 0000000..41f8b9c
--- /dev/null
+++ b/src/test_suite.cpp
@@ -0,0 +1,15 @@
+/** @file test_suite.cpp
+ *
+ *  @author Cory Alexander Balaton (coryab)
+ *  @author Janita Ovidie Sandtrøen Willumsen (janitaws)
+ *
+ *  @version 0.1
+ *
+ *  @brief The test suite for the project
+ *
+ *  @bug No known bugs
+ * */
+int main() 
+{
+    return 0;
+}
diff --git a/src/utils.cpp b/src/utils.cpp
new file mode 100644
index 0000000..0e93a31
--- /dev/null
+++ b/src/utils.cpp
@@ -0,0 +1,28 @@
+/** @file utils.cpp
+ *
+ *  @author Cory Alexander Balaton (coryab)
+ *  @author Janita Ovidie Sandtrøen Willumsen (janitaws)
+ *
+ *  @version 1.0
+ *
+ *  @brief Implementation of the utils
+ *
+ *  @bug No known bugs
+ * */
+#include "utils.hpp"
+
+std::string scientific_format(double d, int width, int prec)
+{
+    std::stringstream ss;
+    ss << std::setw(width) << std::setprecision(prec) << std::scientific << d;
+    return ss.str();
+}
+
+std::string scientific_format(const std::vector<double>& v, int width, int prec)
+{
+    std::stringstream ss;
+    for(double elem : v) {
+        ss << scientific_format(elem, width, prec);
+    }
+    return ss.str();
+}