diff --git a/include/BaseRobot.h b/include/BaseRobot.h
new file mode 100644
index 0000000..918714c
--- /dev/null
+++ b/include/BaseRobot.h
@@ -0,0 +1,28 @@
+#pragma once
+
+#include "Robot.h"
+
+#include <string>
+
+class BaseRobot : public Robot {
+    /* A robot base class that implements functions common to all robots. */
+  public:
+    BaseRobot ( std::string name, int startX, int startY );
+
+    void move ( int direction, const World &world ) override;
+    int decideNextMove ( const World &world ) const override;
+
+    void setPosition ( int x, int y ) override {
+        x_ = x;
+        y_ = y;
+    }
+    int getScore () const override { return score_; }
+    void addScore ( int points ) override { score_ += points; }
+    int getX () const override { return x_; }
+    int getY () const override { return y_; }
+    std::string getName () const override { return name_; }
+
+  protected:
+    int x_, y_, score_;
+    std::string name_;
+};
diff --git a/include/Robot.h b/include/Robot.h
new file mode 100644
index 0000000..280600c
--- /dev/null
+++ b/include/Robot.h
@@ -0,0 +1,31 @@
+#pragma once
+
+#include <string>
+#include <system_error>
+#include <type_traits>
+
+class World;
+
+class Robot {
+    /* A virtual interface for a robot */
+  public:
+    virtual ~Robot () = default;
+    Robot ( const Robot & ) = default;
+    Robot &operator= ( const Robot & ) = default;
+    Robot ( Robot && ) = default;
+    Robot &operator= ( Robot && ) = default;
+
+    virtual void move ( int direction, const World &world ) = 0;
+    virtual int mine ( World &world ) = 0;
+    virtual int decideNextMove ( const World &world ) const = 0;
+
+    virtual void setPosition ( int x, int y ) = 0;
+    virtual int getScore () const = 0;
+    virtual void addScore ( int points ) = 0;
+    virtual int getX () const = 0;
+    virtual int getY () const = 0;
+    virtual std::string getName () const = 0;
+
+  protected:
+    Robot () = default;
+};
diff --git a/include/SortBot.h b/include/SortBot.h
new file mode 100644
index 0000000..d90127f
--- /dev/null
+++ b/include/SortBot.h
@@ -0,0 +1,9 @@
+#pragma once
+
+#include "../include/BaseRobot.h"
+
+class SortBot : public BaseRobot {
+  public:
+    SortBot ( int startX, int startY );
+    int mine ( World &world ) override;
+};
diff --git a/include/World.h b/include/World.h
index 21d60d5..5a0a707 100644
--- a/include/World.h
+++ b/include/World.h
@@ -3,6 +3,9 @@
 #include <vector>
 
 class World {
+    /* A 3D grid world where robots can mine blocks.
+    Blocks have a value, some have special effects. */
+
   public:
     explicit World ( int x = 5, int y = 5, int z = 10 );
 
diff --git a/src/BaseRobot.cpp b/src/BaseRobot.cpp
new file mode 100644
index 0000000..cf634cb
--- /dev/null
+++ b/src/BaseRobot.cpp
@@ -0,0 +1,30 @@
+#include "../include/BaseRobot.h"
+#include "../include/World.h"
+
+#include <algorithm>
+
+BaseRobot::BaseRobot ( std::string name, int startX, int startY )
+    : x_ ( startX ), y_ ( startY ), score_ ( 0 ), name_ ( std::move ( name ) ) {}
+
+void BaseRobot::move ( int direction, const World &world ) {
+
+    switch ( direction ) {
+    case 1:
+        x_ = std::min ( x_ + 1, world.getSizeX() - 1 );
+        break;  // right
+    case 2:
+        x_ = std::max ( x_ - 1, 0 );
+        break;  // left
+    case 3:
+        y_ = std::min ( y_ + 1, world.getSizeY() - 1 );
+        break;  // down
+    case 4:
+        y_ = std::max ( y_ - 1, 0 );
+        break;  // up
+    default:
+        break;  // no move
+    }
+}
+
+// TODO
+// int BaseRobot::decideNextMove ( const World &world ) const
diff --git a/src/SortBot.cpp b/src/SortBot.cpp
new file mode 100644
index 0000000..585480d
--- /dev/null
+++ b/src/SortBot.cpp
@@ -0,0 +1,7 @@
+#include "../include/SortBot.h"
+#include "../include/World.h"
+
+#include <algorithm>
+#include <vector>
+
+SortBot::SortBot ( int startX, int startY ) : BaseRobot ( "SortBot", startX, startY ) {}