diff --git a/include/list.h b/include/list.h
index 2b7efe2..fd77522 100644
--- a/include/list.h
+++ b/include/list.h
@@ -4,17 +4,19 @@
 
 #include <cstddef>
 
+namespace ods {
 
 // Lists are sequences of values.
-template <typename T>
-class List {
-public:
-	virtual std::size_t size(void);
-	virtual T get(std::size_t);
-	virtual T set(std::size_t, T);
-	virtual void add(std:size_t, T);
-	virtual T remove(std::size_t);
-};
+	template <typename T>
+	    class List {
+	public:
+		virtual std::size_t size(void);
+		virtual T get(std::size_t);
+		virtual T set(std::size_t, T);
+		virtual void add(std::size_t, T);
+		virtual T remove(std::size_t);
+	};
 
+} // end namespace ods
 
-#endif
\ No newline at end of file
+#endif
diff --git a/include/simplist.h b/include/simplist.h
new file mode 100644
index 0000000..70b1472
--- /dev/null
+++ b/include/simplist.h
@@ -0,0 +1,24 @@
+#ifndef __ODS_SIMPLIST__
+#define __ODS_SIMPLIST__
+
+#include "list.h"
+
+namespace ods {
+
+	template <typename T>
+	    class SimpList : public List {
+	public:
+		SimpList();
+		std::size_t size(void);
+		T get(std::size_t);
+		T set(std::size_t, T);
+		void add(std::size_t, T);
+		T remove(std::size_t);
+	private:
+		T		arr[];
+		std::size_t	cap;
+		std::size_t	len;
+	};
+
+} // end namespace ods
+#endif
diff --git a/notes/chapter1.txt b/notes/chapter1.txt
index 6285997..de987a5 100644
--- a/notes/chapter1.txt
+++ b/notes/chapter1.txt
@@ -142,6 +142,8 @@ Run times come in three flavours:
    is equal to x. In addition, a Bag supports the findAll(x) operation that
    returns a list of all elements in the Bag that are equal to x.
 
+   In progress: src/ch01ex05.cc.
+
 6. From scratch, write and test implementations of the List, USet and SSet
    interfaces. These do not have to be efficient. They can be used later to
    test the correctness and performance of more efficient implementations.
diff --git a/src/Makefile.am b/src/Makefile.am
index 1215fc1..e0da8fc 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1,9 +1,11 @@
 AM_CPPFLAGS  =  -Wall -Wextra -pedantic -Wshadow -Wpointer-arith -Wcast-align
 AM_CPPFLAGS +=  -Wwrite-strings -Wmissing-declarations -Wno-long-long -Werror
-AM_CPPFLAGS +=  -Wunused-variable -std=c++14 -D_XOPEN_SOURCE -O0 -g -I.
+AM_CPPFLAGS +=  -Wunused-variable -std=c++14 -D_XOPEN_SOURCE -O0 -g -I. -I../include
 AM_CPPFLAGS +=  -fno-elide-constructors -Weffc++
 
-bin_PROGRAMS :=	ch01ex01 ch01ex03 ch01ex04
+bin_PROGRAMS :=	ch01ex01 ch01ex03 ch01ex04 ch01ex05 ch01ex06
 ch01ex01_SOURCES := ch01ex01.cc
 ch01ex03_SOURCES := ch01ex03.cc
 ch01ex04_SOURCES := ch01ex04.cc
+ch01ex05_SOURCES := ch01ex05.cc
+ch01ex06_SOURCES := simplist.cc ch01ex06.cc
diff --git a/src/ch01ex05.cc b/src/ch01ex05.cc
index 0339421..ebe585a 100644
--- a/src/ch01ex05.cc
+++ b/src/ch01ex05.cc
@@ -1,15 +1,22 @@
 #include <iostream>
 #include <vector>
 
-// Using a USet, implement a Bag. A Bag is like a USet supports the add(x),
-// remove(x), and find (x) methods — but it allows duplicate
-// elements to be stored.  The find(x) operation in a Bag returns some element (if any) that is equal to x. In addition,
-// a Bag supports the findAll(x) operation that returns a list of all elements in the Bag that are equal to x.
+// Using a USet, implement a Bag. A Bag is like a USet — it supports the add(x),
+// remove(x), and find (x) methods — but it allows duplicate elements to be
+// stored.  The find(x) operation in a Bag returns some element (if any) that is
+// equal to x. In addition, a Bag supports the findAll(x) operation that returns
+// a list of all elements in the Bag that are equal to x.
 
-template<typename T>
-class Bag {
-public:
+// template<typename T>
+// class Bag {
+// public:
+//
+// private:
+//  	vector<T>	v;
+// };
 
-private:
-	vector<T>	v;
-};
+int
+main(void)
+{
+	return 0;
+}
diff --git a/src/ch01ex06.cc b/src/ch01ex06.cc
new file mode 100644
index 0000000..ec19e5f
--- /dev/null
+++ b/src/ch01ex06.cc
@@ -0,0 +1,22 @@
+#include <cassert>
+#include <simplist.h>
+using namespace std;
+
+
+static void
+check_simplist(void)
+{
+	ods::SimpList<int>	sl;
+
+	sl.add(0, 1);
+	sl.add(1, 2);
+	sl.add(2, 3);
+	assert(sl.size() == 3);
+}
+
+
+int
+main(void)
+{
+	check_simplist();
+}
diff --git a/src/simplist.cc b/src/simplist.cc
new file mode 100644
index 0000000..988fd92
--- /dev/null
+++ b/src/simplist.cc
@@ -0,0 +1,48 @@
+#include "simplist.h"
+#include <cassert>
+#include <cstdlib>
+#include <stdexcept>
+
+constexpr	std::size_t DEFAULT_SIZE =	8;
+
+namespace ods {
+
+	SimpList<T>::SimpList<T>()
+	{
+		this->arr = new T[DEFAULT_SIZE];
+		this->cap = 0;
+		this->len = 0;
+	}
+
+
+	std::size_t
+	SimpList<T> size(void)
+	{
+		std::assert(len <= cap);
+		return this->len();
+	}
+
+	T
+	SimpList<T>::get(std::size_t i)
+	{
+		throw std::invalid_argument("invalid argument");
+	}
+
+	T
+	SimpList<T>::set(std::size_t, T)
+	{
+		throw std::invalid_argument("invalid argument");
+	}
+
+	void
+	SimpList<T>::add(std::size_t, T)
+	{
+		return;
+	}
+
+	T
+	SimpList<T>::remove(std::size_t)
+	{
+		throw std::invalid_argument("invalid argument");
+	}
+};