diff --git a/autobuild b/autobuild
index 1f94136..d82c3d3 100644
--- a/autobuild
+++ b/autobuild
@@ -21,6 +21,8 @@ then
 	mkdir -p $BUILDDIR && cd $BUILDDIR
 	autoreconf -i $SRCDIR
 	bash $SRCDIR/configure $CONFOPTS
+	[ -d "$BUILDDIR/data" ] || mkdir "$BUILDDIR/data"
+	cp $SRCDIR/data/corpus* "$BUILDDIR/data"
 else
 	autoreconf -i
 	./configure $CONFOPTS
diff --git a/data/Makefile.am b/data/Makefile.am
index fe964cc..dbd6f14 100644
--- a/data/Makefile.am
+++ b/data/Makefile.am
@@ -8,5 +8,5 @@ ods-cpp/main.cpp: ods-cpp.tgz
 
 ODS_SAMPLE_CODE_URL :=		http://opendatastructures.org/ods-cpp.tgz
 ods-cpp.tgz:
-	if command -v curl 2>&1 > /dev/null ; then curl -L -O $(ODS_SAMPLE_CODE_URL) \
+	if command -v curl 2>&1 > /dev/null ; then curl -L -O $(ODS_SAMPLE_CODE_URL) ; \
 	elif command -v curl 2>&1 > /dev/null ; then wget $(ODS_SAMPLE_CODE_URL) ; fi
diff --git a/notes/chapter1.txt b/notes/chapter1.txt
index de987a5..e041813 100644
--- a/notes/chapter1.txt
+++ b/notes/chapter1.txt
@@ -148,6 +148,8 @@ Run times come in three flavours:
    interfaces. These do not have to be efficient. They can be used later to
    test the correctness and performance of more efficient implementations.
 
+   In progress: src/ch01ex06.cc, src/ods/simplist.h, src/ods/uset.h.
+
 7. Work to improve the performance of your implementations
    from the previous question using any tricks you can think of. Experiment
    and think about how you could improve the performance of add(i,x) and
diff --git a/src/Makefile.am b/src/Makefile.am
index b9b101b..9778194 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1,6 +1,6 @@
 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++17 -D_XOPEN_SOURCE -O0 -g -I.
 AM_CPPFLAGS +=  -fno-elide-constructors -Weffc++
 
 bin_PROGRAMS :=		ch01ex01 ch01ex03 ch01ex04 ch01ex05 ch01ex06
diff --git a/src/ch01ex06.cc b/src/ch01ex06.cc
index 7b23901..d186043 100644
--- a/src/ch01ex06.cc
+++ b/src/ch01ex06.cc
@@ -1,5 +1,7 @@
 #include <cassert>
+#include <iostream>
 #include <ods/simplist.h>
+#include <ods/simpuset.h>
 using namespace std;
 
 
@@ -12,6 +14,54 @@ check_simplist(void)
 	sl.add(1, 2);
 	sl.add(2, 3);
 	assert(sl.size() == 3);
+	
+	sl.add(0, 4);
+	sl.add(1, 5);
+	sl.add(2, 6);
+	assert(sl.size() == 6);
+	
+	int	expected[6] = {4, 5, 6, 1, 2, 3};
+	for (size_t i = 0; i < 6; i++) {
+		assert(sl.get(i) == expected[i]);
+	}
+	
+	bool caught = false;
+	try {
+		sl.add(8, 8);
+	} catch (std::invalid_argument) {
+		caught = true;
+	}
+	assert(caught);
+	
+	assert(sl.get(2) == 6);
+	sl.remove(2);
+	assert(sl.get(2) == 1);
+	assert(sl.size() == 5);
+	sl.set(2, 6);
+	assert(sl.get(2) == 6);
+	
+	// expected = {1, 2, 3, 4, 5, 6};
+	for (size_t i = 0; i < 6; i++) {
+		expected[i] = i+1;
+	}
+
+	for (size_t i = 0; i < 5; i++) {
+		sl.set(i, i+1);
+	}
+	sl.add(5, 6);
+	
+	for (size_t i = 0; i < 6; i++) {
+		assert(sl.get(i) == expected[i]);
+	}
+}
+
+
+static void
+check_simpuset(void)
+{
+	ods::SimpUSet<int>	us;
+	
+	assert(us.add(1));
 }
 
 
@@ -19,4 +69,6 @@ int
 main(void)
 {
 	check_simplist();
+	check_simpuset();
+	cout << "OK" << endl;
 }