diff --git a/example/ex-bptree01.c b/example/ex-bptree01.c
new file mode 100644
index 00000000..209c3b81
--- /dev/null
+++ b/example/ex-bptree01.c
@@ -0,0 +1,60 @@
+#include "m-bptree.h"
+#include "m-string.h"
+
+// Define a map int -> string
+BPTREE_DEF2(map_employee_id, 5, int, string_t)
+#define M_OPL_map_employee_id_t() BPTREE_OPLIST2(map_employee_id, M_DEFAULT_OPLIST, STRING_OPLIST)
+
+// Define a map string -> int
+BPTREE_DEF2(map_employee_name, 5, string_t, int)
+#define M_OPL_map_employee_name_t() BPTREE_OPLIST2(map_employee_name, STRING_OPLIST, M_DEFAULT_OPLIST)
+
+int main(void)
+{
+  map_employee_id_t Employees;
+  map_employee_id_init(Employees);
+
+  // Assign
+  map_employee_id_set_at(Employees, 17425, STRING_CTE("Mike"));
+  map_employee_id_set_at(Employees, 7147, STRING_CTE("Tango"));
+  map_employee_id_set_at(Employees, 841, STRING_CTE("Charlie"));
+  map_employee_id_set_at(Employees, 11632, STRING_CTE("John Do"));
+  map_employee_id_set_at(Employees, 852, STRING_CTE("Peter"));
+  map_employee_id_set_at(Employees, 530, STRING_CTE("Amanda"));
+  map_employee_id_set_at(Employees, 4258, STRING_CTE("Elisabeth"));
+
+  printf("Number of employees: %zu\n", map_employee_id_size(Employees));
+
+  // Iterate over the employee list
+  printf("\nList of employees (sorted by id):\n");
+  map_employee_id_it_t it;
+  for(map_employee_id_it(it, Employees); !map_employee_id_end_p(it); map_employee_id_next(it)) {
+    // Get a pointer to this employee from the iterator
+    const map_employee_id_type_t *e = map_employee_id_cref(it);
+    // Print it
+    printf ("%d: %s\n", *(e->key_ptr), string_get_cstr(*(e->value_ptr)));
+  }
+
+  // Let's create a reverse map
+  M_LET(Employees_r, map_employee_name_t) {
+
+    // Let's fill in the reverse map with each employee
+    // (using macro M_EACH)
+    for M_EACH(e, Employees, map_employee_id_t) {
+        map_employee_name_set_at(Employees_r, *(e->value_ptr), *(e->key_ptr));
+      }
+
+    // Iterate over the employee list
+    printf("\nList of employees (sorted by name):\n");
+    for M_EACH(e, Employees_r, map_employee_name_t) {
+        printf ("%d: %s\n", *(e->value_ptr), string_get_cstr(*(e->key_ptr)));
+      }
+
+    // Print
+    printf("\nElisabeth has id = %d\n", *map_employee_name_get(Employees_r, STRING_CTE("Elisabeth")));
+    
+  }
+
+  map_employee_id_clear(Employees);
+  return 0;
+}