diff --git a/Matrix.h b/Matrix.h
index b9b9d18..314b0a0 100644
--- a/Matrix.h
+++ b/Matrix.h
@@ -7,7 +7,7 @@
 template <typename T> class MatrixOf {
 public:
   MatrixOf(unsigned int rows, unsigned int cols);
-  MatrixOf(unsigned int rows, unsigned int cols, T *source)
+  MatrixOf(unsigned int rows, unsigned int cols, const T *source)
       : MatrixOf(rows, cols) {
     Set(source);
   }
@@ -60,7 +60,7 @@ public:
   static Vector3 Multiply(const MatrixOf<T> *m, Vector3 v);
   Vector3 operator*(const Vector3 v) const;
 
-  T Get(unsigned int rowIx, unsigned int colIx) {
+  T Get(unsigned int rowIx, unsigned int colIx) const {
     unsigned int dataIx = rowIx * this->cols + colIx;
     return this->data[dataIx];
   }
@@ -71,7 +71,7 @@ public:
   }
 
   // This function does not check on source size!
-  void Set(T *source) {
+  void Set(const T *source) {
     unsigned int matrixSize = this->cols * this->rows;
     for (unsigned int dataIx = 0; dataIx < matrixSize; dataIx++)
       this->data[dataIx] = source[dataIx];