diff --git a/src/core/CLI.cpp b/src/cli/CLI.cpp
similarity index 100%
rename from src/core/CLI.cpp
rename to src/cli/CLI.cpp
diff --git a/src/core/CLI.h b/src/cli/CLI.h
similarity index 100%
rename from src/core/CLI.h
rename to src/cli/CLI.h
diff --git a/src/core/CLIParser.cpp b/src/cli/CLIParser.cpp
similarity index 100%
rename from src/core/CLIParser.cpp
rename to src/cli/CLIParser.cpp
diff --git a/src/core/CLIParser.h b/src/cli/CLIParser.h
similarity index 100%
rename from src/core/CLIParser.h
rename to src/cli/CLIParser.h
diff --git a/src/core/ImageMatcher.h b/src/core/ImageMatcher.h
deleted file mode 100644
index 73e7ae5..0000000
--- a/src/core/ImageMatcher.h
+++ /dev/null
@@ -1,10 +0,0 @@
-#pragma once
-
-
-
-class ImageMatcher{
-public:
-
-private:
-
-};
diff --git a/src/core/Picker.cpp b/src/core/Picker.cpp
new file mode 100644
index 0000000..7667a1e
--- /dev/null
+++ b/src/core/Picker.cpp
@@ -0,0 +1,18 @@
+#include "Picker.h"
+
+using namespace core;
+
+
+Picker::Picker() {}
+
+Picker::~Picker() {}
+
+Colour Picker::match(Colour obj, Colour* picks) {
+  // TODO: matching code
+  return Colour(0.0f, 0.0f, 0.0f);
+}
+
+std::vector<Colour> match_multi(Colour* obj, Colour* picks) {
+  // TODO: idem ditto
+  return std::vector<Colour>();
+}
diff --git a/src/core/Picker.h b/src/core/Picker.h
new file mode 100644
index 0000000..344f532
--- /dev/null
+++ b/src/core/Picker.h
@@ -0,0 +1,15 @@
+#pragma once
+
+#include "Colour.h"
+#include <vector>
+
+namespace core {
+class Picker{
+public:
+  Picker();
+  ~Picker();
+
+  Colour match(Colour obj, Colour* picks);
+  std::vector<Colour> match_multi(Colour* obj, Colour* picks);
+};
+}
diff --git a/src/core/RGBMatcher.cpp b/src/core/RGBMatcher.cpp
deleted file mode 100644
index e69de29..0000000
diff --git a/src/core/RGBMatcher.h b/src/core/RGBMatcher.h
deleted file mode 100644
index e69de29..0000000
diff --git a/src/core/matchers/ImageMatcher.h b/src/core/matchers/ImageMatcher.h
deleted file mode 100644
index 73e7ae5..0000000
--- a/src/core/matchers/ImageMatcher.h
+++ /dev/null
@@ -1,10 +0,0 @@
-#pragma once
-
-
-
-class ImageMatcher{
-public:
-
-private:
-
-};
diff --git a/src/core/matchers/Matcher.h b/src/core/matchers/Matcher.h
new file mode 100644
index 0000000..7b6940a
--- /dev/null
+++ b/src/core/matchers/Matcher.h
@@ -0,0 +1,12 @@
+#pragma once
+
+#include "../Colour.h"
+
+namespace core {
+
+class Matcher {
+public:
+  virtual float distance(const Colour a, const Colour b) ;
+  virtual float luminance(const Colour a) ;
+};
+}
diff --git a/src/core/matchers/RGBMatcher.h b/src/core/matchers/RGBMatcher.h
index e69de29..08bab48 100644
--- a/src/core/matchers/RGBMatcher.h
+++ b/src/core/matchers/RGBMatcher.h
@@ -0,0 +1,12 @@
+#pragma once
+
+
+#include "Matcher.h"
+
+
+namespace core {
+class RGBMatcher : Matcher {
+  float distance(const Colour a, const Colour b);
+  float luminance(const Colour a);
+};
+}