diff --git a/example/box_example.cpp b/example/box_example.cpp
index c91ffdf2..0aa335cd 100644
--- a/example/box_example.cpp
+++ b/example/box_example.cpp
@@ -31,6 +31,10 @@
 #include <iostream>
 #include <utility>
 
+template<class T>
+  requires units::is_scalar<T>
+inline constexpr bool units::is_vector<T> = true;
+
 namespace {
 
 using namespace units;
@@ -57,7 +61,7 @@ public:
     return quantity_cast<isq::weight>(mass * g);
   }
 
-  [[nodiscard]] constexpr quantity<isq::length[m]> fill_level(const quantity<isq::mass[kg]>& measured_mass) const
+  [[nodiscard]] constexpr quantity<isq::height[m]> fill_level(const quantity<isq::mass[kg]>& measured_mass) const
   {
     return height_ * measured_mass * g / filled_weight();
   }
diff --git a/example/measurement.cpp b/example/measurement.cpp
index e4f8881f..6d43de1f 100644
--- a/example/measurement.cpp
+++ b/example/measurement.cpp
@@ -117,11 +117,15 @@ private:
 
 }  // namespace
 
+template<class T>
+inline constexpr bool units::is_scalar<measurement<T>> = true;
+template<class T>
+inline constexpr bool units::is_vector<measurement<T>> = true;
+
+static_assert(units::RepresentationOf<measurement<double>, units::quantity_character::scalar>);
 
 namespace {
 
-static_assert(units::Representation<measurement<double>>);
-
 void example()
 {
   using namespace units;
@@ -130,7 +134,7 @@ void example()
   const auto a = measurement{9.8, 0.1} * isq::acceleration[m / s2];
   const auto t = measurement{1.2, 0.1} * isq::time[s];
 
-  const weak_quantity_of<isq::speed> auto v = a * t;
+  const weak_quantity_of<isq::velocity> auto v = a * t;
   std::cout << a << " * " << t << " = " << v << " = " << v[km / h] << '\n';
 
   const auto length = measurement{123., 1.} * isq::length[si::metre];
diff --git a/example/si_constants.cpp b/example/si_constants.cpp
index f703fd71..966b23cd 100644
--- a/example/si_constants.cpp
+++ b/example/si_constants.cpp
@@ -25,6 +25,10 @@
 #include <units/si/unit_symbols.h>
 #include <iostream>
 
+template<class T>
+  requires units::is_scalar<T>
+inline constexpr bool units::is_vector<T> = true;
+
 int main()
 {
   using namespace units::si;
diff --git a/test/unit_test/runtime/fmt_test.cpp b/test/unit_test/runtime/fmt_test.cpp
index 2b03b9f6..e5efee04 100644
--- a/test/unit_test/runtime/fmt_test.cpp
+++ b/test/unit_test/runtime/fmt_test.cpp
@@ -34,6 +34,10 @@
 #include <limits>
 #include <locale>
 
+template<class T>
+  requires units::is_scalar<T>
+inline constexpr bool units::is_vector<T> = true;
+
 using namespace units;
 using namespace units::si::unit_symbols;