diff --git a/examples/hexgrid.cpp b/examples/hexgrid.cpp
index f013d2e5..1bc1d8d0 100644
--- a/examples/hexgrid.cpp
+++ b/examples/hexgrid.cpp
@@ -1,109 +1,439 @@
 /*
  * An example mplot::Visual scene, containing hexgrids.
+ *
+ * Hexagonal grids were the first VisualModel I coded in mathplot. The interest in hexgrids came
+ * from Stuart Wilson, who wanted to compute reaction diffusion systems in C++. Those early hexgrids
+ * took part in this paper about whisker barrels: https://elifesciences.org/articles/55588
+ *
+ * This program shows some examples of the hexgrids that you can work with using sm::hexgrid and
+ * mplot::HexGridVisual.
+ *
+ * Author: Seb James
  */
 
 #include <iostream>
 #include <memory>
 #include <vector>
 #include <cmath>
+#include <map>
+#include <list>
+#include <format>
+#include <tuple>
 
 import sm.vec;
 import sm.hexgrid;
+import sm.algo.hexgrid; // hexgrid algorithms, particularly the ability to reduce down to the 'next-coarser' grid
 
 import mplot.visual;
 import mplot.visualdatamodel;
 import mplot.hexgridvisual;
 
+// We make some dummy data (a sine wave) to show on our hexgrids and either colour or elevation
+namespace hexexample
+{
+    template<typename F, sm::hexalign A>
+    void orthogonal_sines (sm::hexgrid<F, A>& hg, sm::vvec<F>& data)
+    {
+        data.resize (hg.num(), F{0});
+        for (unsigned int ri = 0; ri < hg.num(); ++ri) {
+            data[ri] = 0.05f + 0.05f * std::sin (20.0f * hg.d_x[ri]) * std::sin (10.0f * hg.d_y[ri]) ; // Range 0->1
+        }
+    }
+}
+
 int main()
 {
     // Contructor args are width, height, title
-    mplot::Visual<mplot::gl::version_4_1> v(1600, 1000, "mplot::HexGridVisual");
+    mplot::Visual<mplot::gl::version_4_1> v(1800, 1800, "mplot::HexGridVisual examples");
+    // Set inital scene translation
+    v.setSceneTrans (sm::vec<float,3>{ float{-0.635992}, float{0.75472}, float{-6.91652} });
     // You can set a field of view (in degrees)
     v.fov = 15;
-    // set the x/y offset. Try pressing 'z' in the app window to see what the current sceneTrans is
-    v.setSceneTransXY (0.0f, 0.0f);
-    // Make this larger to "scroll in and out of the image" faster. 0.02f is the default in VisualBase.
-    v.scenetrans_stepsize = 0.02f;
-    // The coordinate arrows can be hidden
-    v.showCoordArrows (true);
+    // The coordinate arrows can be shown/hidden
+    v.showCoordArrows (false);
     // You can set the background (white, black, or any other colour)
     v.backgroundWhite();
     // You can switch on the "lighting shader" which puts diffuse light into the scene
     v.lightingEffects();
-    // Add some text labels to the scene
-    //v.addLabel ("This is a\nmplot::HexGridVisual\nobject", {0.26f, -0.16f, 0.0f});
+    v.rotateAboutNearest (true);
 
-    // Create a HexGrid to show in the scene. Hexes outside the circular boundary will
-    // all be discarded.
+    // Create a HexGrid to show in the scene. Hexes outside the circular boundary will all be
+    // discarded.
     sm::hexgrid<float, sm::hexalign::point_up> hg1(0.01f, 0.205f, 0.0f);
-    //hg1.set_circular_boundary (0.1f);
-    hg1.set_boundary_on_outer_edge();
-    std::cout << "Number of pixels in point_up grid:" << hg1.num() << std::endl;
+    hg1.set_circular_boundary (0.1f);
+    // Make data for hg1
+    sm::vvec<float> data1 = {};
+    hexexample::orthogonal_sines (hg1, data1);
 
+    // A second hexgrid and data. This is a 'flat_up' grid
     sm::hexgrid<float, sm::hexalign::flat_up> hg2(0.01f, 0.205f, 0.0f);
-    //hg2.set_circular_boundary (0.1f);
     hg2.set_boundary_on_outer_edge();
-    std::cout << "Number of pixels in flat_up grid:" << hg2.num() << std::endl;
+    sm::vvec<float> data2 = {};
+    hexexample::orthogonal_sines (hg2, data2);
 
-    // Make some dummy data (a sine wave) to make an interesting surface
-    std::vector<float> data1(hg1.num(), 0.0f);
-    for (unsigned int ri = 0; ri < hg1.num(); ++ri) {
-        data1[ri] = 0.05f + 0.05f * std::sin (20.0f * hg1.d_x[ri]) * std::sin (10.0f * hg1.d_y[ri]) ; // Range 0->1
-    }
-    std::vector<float> data2(hg2.num(), 0.0f);
-    for (unsigned int ri = 0; ri < hg2.num(); ++ri) {
-        data2[ri] = 0.05f + 0.05f * std::sin (20.0f * hg2.d_x[ri]) * std::sin (10.0f * hg2.d_y[ri]) ; // Range 0->1
-    }
+    // Reduced hexgrid, copied from hg1r
+    sm::hexgrid<float, sm::hexalign::point_up> hg1r = sm::algo::hexgrid::reduced_hexgrid (hg1);
+    sm::vvec<float> data1r = {};
+    hexexample::orthogonal_sines (hg1r, data1r);
+
+    // Doubly reduced hexgrid
+    sm::hexgrid<float, sm::hexalign::point_up> hg1rr = sm::algo::hexgrid::reduced_hexgrid (hg1r);
+    sm::vvec<float> data1rr = {};
+    hexexample::orthogonal_sines (hg1rr, data1rr);
+
+    // And again
+    sm::hexgrid<float, sm::hexalign::point_up> hg1rrr = sm::algo::hexgrid::reduced_hexgrid (hg1rr);
+    sm::vvec<float> data1rrr = {};
+    hexexample::orthogonal_sines (hg1rrr, data1rrr);
+
+    // More flat up grids (for reduction)
+    sm::hexgrid<float, sm::hexalign::flat_up> hgf1(0.01f, 0.205f, 0.0f);
+    hgf1.set_circular_boundary (0.1f);
+    sm::vvec<float> dataf1 = {};
+    hexexample::orthogonal_sines (hgf1, dataf1);
+
+    // Create a reduced hexgrid
+    sm::hexgrid<float, sm::hexalign::flat_up> hgf1r = sm::algo::hexgrid::reduced_hexgrid (hgf1);
+    // Regenerate data for hgf1r
+    sm::vvec<float> dataf1r = {};
+    hexexample::orthogonal_sines (hgf1r, dataf1r);
+    // Also *map* data from dataf1 onto dataf1r_mapped
+    auto mapping1 = sm::algo::hexgrid::reduced_hexgrid_mapping (hgf1, hgf1r);
+    sm::vvec<float> dataf1r_mapped = {};
+    sm::algo::hexgrid::map_to_reduced_hexgrid (mapping1, dataf1, dataf1r_mapped);
+
+    sm::hexgrid<float, sm::hexalign::flat_up> hgf1rr = sm::algo::hexgrid::reduced_hexgrid (hgf1r);
+    sm::vvec<float> dataf1rr = {};
+    hexexample::orthogonal_sines (hgf1rr, dataf1rr);
 
-    // sm::HexVisMode::HexInterp to see the hexagons or sm::HexVisMode::Triangles for a smoother surface plot
-    const mplot::HexVisMode visMode = mplot::HexVisMode::HexInterp;
+    // Layout parameters
+    constexpr float rh = 0.46f; // row height
+    constexpr float cw = 0.3f; // col width
+    sm::vec<float> label_pos = { -0.1f, -0.15f, 0.0f };
+    const mplot::TextFeatures tf(0.02f);
+
+    /*
+     * Row 1
+     */
 
     // Add a HexGridVisual to display the HexGrid within the sm::Visual scene
-    sm::vec<float, 3> offset = { 0.0f, -0.05f, 0.0f };
-    auto hgv1 = std::make_unique<mplot::HexGridVisual<float, sm::hexalign::point_up, mplot::gl::version_4_1>>(&hg1, offset);
-    hgv1->set_parent (v.get_id());
-    hgv1->cm.setType (mplot::ColourMapType::Ice);
-    hgv1->setScalarData (&data1);
-    hgv1->hexVisMode = visMode;
-    hgv1->zScale.null_scaling();
-    hgv1->addLabel ("hexalign::point_up", sm::vec<>{ -hg1.width()/2.1f, -hg1.width()/1.6f }, mplot::TextFeatures(0.02f));
-    hgv1->finalize();
-    v.addVisualModel (hgv1);
-
-    offset[0] += 1.1f * hg1.width();
-    auto hgv2 = std::make_unique<mplot::HexGridVisual<float, sm::hexalign::flat_up, mplot::gl::version_4_1>>(&hg2, offset);
-    hgv2->set_parent (v.get_id());
-    hgv2->cm.setType (mplot::ColourMapType::Ice);
-    hgv2->setScalarData (&data2);
-    hgv2->hexVisMode = visMode;
-    hgv2->zScale.null_scaling();
-    // You can transform the view of the hexgrid in HexGridVisual (transforms may also be applied to the underlying hexgrid)
-    // This applies a scaling first, and then a reflection.
-    //hgv2->tfm = sm::mat<float, 3>::reflection (sm::vec<float>::ux()) * sm::mat<float, 3>::identity() * 0.5f;
-    hgv2->addLabel ("hexalign::flat_up", sm::vec<>{ -hg1.width()/2.6f, -hg1.width()/1.6f }, mplot::TextFeatures(0.02f));
-    hgv2->finalize();
-
-    if (v.checkContext() == true) {
-        std::cout << "I have the context after hgv->finalize()\n";
-    } else {
-        std::cout << "I don't have the context after hgv->finalize()\n";
-    }
+    sm::vec<float, 3> offset = { 0.0f, 0.0f, 0.0f };
+    auto hgv_pu = std::make_unique<mplot::HexGridVisual<float, sm::hexalign::point_up, mplot::gl::version_4_1>>(&hg1, offset);
+    hgv_pu->set_parent (v.get_id());
+    hgv_pu->cm.setType (mplot::ColourMapType::CET_L04);
+    hgv_pu->setScalarData (&data1);
+    hgv_pu->hexVisMode = mplot::HexVisMode::HexInterp;
+    hgv_pu->addLabel ("hexalign::point_up\n3D (value is z and colour)\ncircular boundary\nboundary not shown\nHexVisMode::HexInterp\nColourMapType::CET_L04",
+                      label_pos, tf);
+    hgv_pu->finalize();
+    v.addVisualModel (hgv_pu);
 
-    v.addVisualModel (hgv2);
+    offset[0] += cw;
+    auto hgv_fl = std::make_unique<mplot::HexGridVisual<float, sm::hexalign::flat_up, mplot::gl::version_4_1>>(&hg2, offset);
+    hgv_fl->set_parent (v.get_id());
+    hgv_fl->cm.setType (mplot::ColourMapType::Cork);
+    hgv_fl->showboundary = true;
+    hgv_fl->setScalarData (&data2);
+    hgv_fl->hexVisMode = mplot::HexVisMode::HexInterp;
+    hgv_fl->zScale.null_scaling();
+    hgv_fl->addLabel ("hexalign::flat_up\n2D (value is only colour)\noriginal hex boundary\nboundary indicated in black\nHexVisMode::HexInterp\nColourMapType::Cork",
+                      label_pos, tf);
+    hgv_fl->finalize();
+    v.addVisualModel (hgv_fl);
 
-    if (v.checkContext() == true) {
-        std::cout << "I have the context after addVisualModel\n";
-    } else {
-        std::cout << "I don't have the context after addVisualModel()\n";
-    }
+    offset[0] += cw;
+    hgv_pu = std::make_unique<mplot::HexGridVisual<float, sm::hexalign::point_up, mplot::gl::version_4_1>>(&hg1, offset);
+    hgv_pu->set_parent (v.get_id());
+    hgv_pu->cm.setType (mplot::ColourMapType::Batlow);
+    hgv_pu->showboundary = true;
+    hgv_pu->setScalarData (&data1);
+    hgv_pu->hexVisMode = mplot::HexVisMode::Triangles;
+    hgv_pu->zScale.null_scaling();
+    hgv_pu->addLabel ("hexalign::point_up\n2D\ncircular boundary\nboundary shown\nHexVisMode::Triangles\nColourMapType::Batlow",
+                      label_pos, tf);
+    hgv_pu->finalize();
+    v.addVisualModel (hgv_pu);
 
-    v.keepOpen();
+    offset[0] += cw;
+    hgv_pu = std::make_unique<mplot::HexGridVisual<float, sm::hexalign::point_up, mplot::gl::version_4_1>>(&hg1, offset);
+    hgv_pu->set_parent (v.get_id());
+    hgv_pu->cm.setType (mplot::ColourMapType::Plasma);
+    hgv_pu->showboundary = true;
+    hgv_pu->setScalarData (&data1);
+    hgv_pu->hexVisMode = mplot::HexVisMode::HexInterp;
+    hgv_pu->zScale.null_scaling();
+    hgv_pu->addLabel ("hexalign::point_up\n2D\ncircular boundary\nboundary shown\nHexVisMode::HexInterp\nColourMapType::Plasma",
+                      label_pos, tf);
+    hgv_pu->finalize();
+    v.addVisualModel (hgv_pu);
 
-    if (v.checkContext() == true) {
-        std::cout << "I have the context after user requested exit\n";
-    } else {
-        std::cout << "I don't have the context after user requested exit\n";
-    }
+    offset[0] += cw;
+    hgv_pu = std::make_unique<mplot::HexGridVisual<float, sm::hexalign::point_up, mplot::gl::version_4_1>>(&hg1, offset);
+    hgv_pu->set_parent (v.get_id());
+    hgv_pu->cm.setType (mplot::ColourMapType::Acton);
+    hgv_pu->showboundary = true;
+    hgv_pu->setScalarData (&data1);
+    hgv_pu->hexVisMode = mplot::HexVisMode::HexInterp;
+    hgv_pu->addLabel ("hexalign::point_up\n3D (boundary always at z=0)\ncircular boundary\nboundary shown\nHexVisMode::HexInterp\nColourMapType::Acton",
+                      label_pos, tf);
+    hgv_pu->finalize();
+    v.addVisualModel (hgv_pu);
+
+    /*
+     * Row 2
+     */
+    label_pos = { -0.1f, -0.175f, 0.0f };
+
+    offset = {0.0f, -rh, 0.0f };
+    hgv_pu = std::make_unique<mplot::HexGridVisual<float, sm::hexalign::point_up, mplot::gl::version_4_1>>(&hg1, offset);
+    hgv_pu->set_parent (v.get_id());
+    hgv_pu->cm.setType (mplot::ColourMapType::Ice);
+    hgv_pu->showboundary = true;
+    hgv_pu->setScalarData (&data1);
+    hgv_pu->hexVisMode = mplot::HexVisMode::HexInterp;
+    hgv_pu->zScale.null_scaling();
+    hgv_pu->addLabel ("hexalign::point_up\n2D (flat)\ncircular boundary\nboundary shown\nColourMapType::Ice", label_pos, tf);
+    hgv_pu->finalize();
+    v.addVisualModel (hgv_pu);
+
+    offset = {cw, -rh, 0.01f };
+    hgv_pu = std::make_unique<mplot::HexGridVisual<float, sm::hexalign::point_up, mplot::gl::version_4_1>>(&hg1r, offset);
+    hgv_pu->set_parent (v.get_id());
+    hgv_pu->cm.setType (mplot::ColourMapType::Ice);
+    hgv_pu->showboundary = true;
+    hgv_pu->setScalarData (&data1r);
+    hgv_pu->hexVisMode = mplot::HexVisMode::HexInterp;
+    hgv_pu->zScale.null_scaling();
+    hgv_pu->addLabel ("Grid reduced once", label_pos, tf);
+    hgv_pu->finalize();
+    v.addVisualModel (hgv_pu);
+
+    offset = {2 * cw, -rh, 0.02f };
+    hgv_pu = std::make_unique<mplot::HexGridVisual<float, sm::hexalign::point_up, mplot::gl::version_4_1>>(&hg1rr, offset);
+    hgv_pu->set_parent (v.get_id());
+    hgv_pu->cm.setType (mplot::ColourMapType::Ice);
+    hgv_pu->showboundary = true;
+    hgv_pu->setScalarData (&data1rr);
+    hgv_pu->hexVisMode = mplot::HexVisMode::HexInterp;
+    hgv_pu->zScale.null_scaling();
+    hgv_pu->addLabel ("Grid reduced twice", label_pos, tf);
+    hgv_pu->finalize();
+    v.addVisualModel (hgv_pu);
+
+    offset = {3 * cw, -rh, 0.0f };
+    hgv_pu = std::make_unique<mplot::HexGridVisual<float, sm::hexalign::point_up, mplot::gl::version_4_1>>(&hg1, offset);
+    hgv_pu->set_parent (v.get_id());
+    hgv_pu->cm.setType (mplot::ColourMapType::Ice);
+    hgv_pu->setScalarData (&data1);
+    hgv_pu->hexVisMode = mplot::HexVisMode::HexInterp;
+    hgv_pu->zScale.null_scaling();
+    hgv_pu->addLabel ("Previous 3 shown layered\nLayers separated in z\nTop 2 transparent", label_pos, tf);
+    hgv_pu->finalize();
+    v.addVisualModel (hgv_pu);
+
+    offset = {3 * cw, -rh, 0.01f };
+    hgv_pu = std::make_unique<mplot::HexGridVisual<float, sm::hexalign::point_up, mplot::gl::version_4_1>>(&hg1r, offset);
+    hgv_pu->set_parent (v.get_id());
+    hgv_pu->cm.setType (mplot::ColourMapType::Ice);
+    hgv_pu->showboundary = true;
+    hgv_pu->setAlpha (0.5f);
+    hgv_pu->setScalarData (&data1r);
+    hgv_pu->hexVisMode = mplot::HexVisMode::HexInterp;
+    hgv_pu->zScale.null_scaling();
+    hgv_pu->finalize();
+    v.addVisualModel (hgv_pu);
 
-    return 0;
+    offset = {3 * cw, -rh, 0.02f };
+    hgv_pu = std::make_unique<mplot::HexGridVisual<float, sm::hexalign::point_up, mplot::gl::version_4_1>>(&hg1rr, offset);
+    hgv_pu->set_parent (v.get_id());
+    hgv_pu->cm.setType (mplot::ColourMapType::Ice);
+    hgv_pu->showboundary = true;
+    hgv_pu->setAlpha (0.5f);
+    hgv_pu->setScalarData (&data1rr);
+    hgv_pu->hexVisMode = mplot::HexVisMode::HexInterp;
+    hgv_pu->zScale.null_scaling();
+    hgv_pu->finalize();
+    v.addVisualModel (hgv_pu);
+
+    /*
+     * Row 3
+     */
+
+    offset = {0.0f, -2 * rh, 0.0f };
+    hgv_fl = std::make_unique<mplot::HexGridVisual<float, sm::hexalign::flat_up, mplot::gl::version_4_1>>(&hgf1, offset);
+    hgv_fl->set_parent (v.get_id());
+    hgv_fl->cm.setType (mplot::ColourMapType::CET_L07);
+    hgv_fl->showboundary = true;
+    hgv_fl->setScalarData (&dataf1);
+    hgv_fl->hexVisMode = mplot::HexVisMode::HexInterp;
+    hgv_fl->zScale.null_scaling();
+    hgv_fl->addLabel ("hexalign::flat_up\n2D (flat)\ncircular boundary\nboundary shown\nColourMapType::CET_L07", label_pos, tf);
+    hgv_fl->finalize();
+    v.addVisualModel (hgv_fl);
+
+    offset = {cw, -2 * rh, 0.01f };
+    hgv_fl = std::make_unique<mplot::HexGridVisual<float, sm::hexalign::flat_up, mplot::gl::version_4_1>>(&hgf1r, offset);
+    hgv_fl->set_parent (v.get_id());
+    hgv_fl->cm.setType (mplot::ColourMapType::CET_L07);
+    hgv_fl->showboundary = true;
+    hgv_fl->setScalarData (&dataf1r);
+    hgv_fl->hexVisMode = mplot::HexVisMode::HexInterp;
+    hgv_fl->zScale.null_scaling();
+    hgv_fl->addLabel ("Grid reduced once\nData regenerated", label_pos, tf);
+    hgv_fl->finalize();
+    v.addVisualModel (hgv_fl);
+
+    offset = {2 * cw, -2 * rh, 0.01f };
+    hgv_fl = std::make_unique<mplot::HexGridVisual<float, sm::hexalign::flat_up, mplot::gl::version_4_1>>(&hgf1r, offset);
+    hgv_fl->set_parent (v.get_id());
+    hgv_fl->cm.setType (mplot::ColourMapType::CET_L07);
+    hgv_fl->showboundary = true;
+    hgv_fl->setScalarData (&dataf1r_mapped);
+    hgv_fl->hexVisMode = mplot::HexVisMode::HexInterp;
+    hgv_fl->zScale.null_scaling();
+    hgv_fl->addLabel ("Grid reduced once\nData mapped", label_pos, tf);
+    hgv_fl->finalize();
+    v.addVisualModel (hgv_fl);
+
+    offset = {3 * cw, -2 * rh, 0.02f };
+    hgv_fl = std::make_unique<mplot::HexGridVisual<float, sm::hexalign::flat_up, mplot::gl::version_4_1>>(&hgf1rr, offset);
+    hgv_fl->set_parent (v.get_id());
+    hgv_fl->cm.setType (mplot::ColourMapType::CET_L07);
+    hgv_fl->showboundary = true;
+    hgv_fl->setScalarData (&dataf1rr);
+    hgv_fl->hexVisMode = mplot::HexVisMode::HexInterp;
+    hgv_fl->zScale.null_scaling();
+    hgv_fl->addLabel ("Grid reduced twice", label_pos, tf);
+    hgv_fl->finalize();
+    v.addVisualModel (hgv_fl);
+
+    offset = {4 * cw, -2 * rh, 0.0f };
+    hgv_fl = std::make_unique<mplot::HexGridVisual<float, sm::hexalign::flat_up, mplot::gl::version_4_1>>(&hgf1, offset);
+    hgv_fl->set_parent (v.get_id());
+    hgv_fl->cm.setType (mplot::ColourMapType::CET_L07);
+    hgv_fl->setScalarData (&dataf1);
+    hgv_fl->hexVisMode = mplot::HexVisMode::HexInterp;
+    hgv_fl->zScale.null_scaling();
+    hgv_fl->addLabel ("Previous 3 shown layered\nLayers separated in z\nUpper two have setAlpha(0.5)", label_pos, tf);
+    hgv_fl->finalize();
+    v.addVisualModel (hgv_fl);
+
+    offset = {4 * cw, -2 * rh, 0.01f };
+    hgv_fl = std::make_unique<mplot::HexGridVisual<float, sm::hexalign::flat_up, mplot::gl::version_4_1>>(&hgf1r, offset);
+    hgv_fl->set_parent (v.get_id());
+    hgv_fl->cm.setType (mplot::ColourMapType::CET_L07);
+    hgv_fl->showboundary = true;
+    hgv_fl->setAlpha (0.5f);
+    hgv_fl->setScalarData (&dataf1r);
+    hgv_fl->hexVisMode = mplot::HexVisMode::HexInterp;
+    hgv_fl->zScale.null_scaling();
+    hgv_fl->finalize();
+    v.addVisualModel (hgv_fl);
+
+    offset = {4 * cw, -2 * rh, 0.02f };
+    hgv_fl = std::make_unique<mplot::HexGridVisual<float, sm::hexalign::flat_up, mplot::gl::version_4_1>>(&hgf1rr, offset);
+    hgv_fl->set_parent (v.get_id());
+    hgv_fl->cm.setType (mplot::ColourMapType::CET_L07);
+    hgv_fl->showboundary = true;
+    hgv_fl->setAlpha (0.5f);
+    hgv_fl->setScalarData (&dataf1rr);
+    hgv_fl->hexVisMode = mplot::HexVisMode::HexInterp;
+    hgv_fl->zScale.null_scaling();
+    hgv_fl->finalize();
+    v.addVisualModel (hgv_fl);
+
+    /*
+     * Row 3
+     */
+    sm::mat<float, 2> rotn;
+    rotn.rotate (sm::mathconst<float>::pi_over_4);
+    hgf1.transform (rotn);
+
+    // Regenerate data/reduced grids
+    hexexample::orthogonal_sines (hgf1, dataf1);
+
+    sm::hexgrid<float, sm::hexalign::flat_up> hgf1rt = sm::algo::hexgrid::reduced_hexgrid (hgf1);
+    // Regenerate data for hgf1rt
+    sm::vvec<float> dataf1rt = {};
+    hexexample::orthogonal_sines (hgf1r, dataf1rt);
+
+    sm::hexgrid<float, sm::hexalign::flat_up> hgf1rrt = sm::algo::hexgrid::reduced_hexgrid (hgf1rt);
+    sm::vvec<float> dataf1rrt = {};
+    hexexample::orthogonal_sines (hgf1rrt, dataf1rrt);
+
+    offset = {0.0f, -3 * rh, 0.0f };
+    hgv_fl = std::make_unique<mplot::HexGridVisual<float, sm::hexalign::flat_up, mplot::gl::version_4_1>>(&hgf1, offset);
+    hgv_fl->set_parent (v.get_id());
+    hgv_fl->cm.setType (mplot::ColourMapType::Ocean);
+    hgv_fl->showboundary = true;
+    hgv_fl->setScalarData (&dataf1);
+    hgv_fl->hexVisMode = mplot::HexVisMode::HexInterp;
+    hgv_fl->zScale.null_scaling();
+    hgv_fl->addLabel ("flat_up, rotated pi/4 (ccw)\n2D (flat)\ncircular boundary\nboundary shown\nColourMapType::Ocean", label_pos, tf);
+    hgv_fl->finalize();
+    v.addVisualModel (hgv_fl);
+
+    offset = {cw, -3 * rh, 0.01f };
+    hgv_fl = std::make_unique<mplot::HexGridVisual<float, sm::hexalign::flat_up, mplot::gl::version_4_1>>(&hgf1rt, offset);
+    hgv_fl->set_parent (v.get_id());
+    hgv_fl->cm.setType (mplot::ColourMapType::Ocean);
+    hgv_fl->showboundary = true;
+    hgv_fl->setScalarData (&dataf1rt);
+    hgv_fl->hexVisMode = mplot::HexVisMode::HexInterp;
+    hgv_fl->zScale.null_scaling();
+    hgv_fl->addLabel ("Grid reduced once\nData regenerated", label_pos, tf);
+    hgv_fl->finalize();
+    v.addVisualModel (hgv_fl);
+
+    offset = {2 * cw, -3 * rh, 0.02f };
+    hgv_fl = std::make_unique<mplot::HexGridVisual<float, sm::hexalign::flat_up, mplot::gl::version_4_1>>(&hgf1rrt, offset);
+    hgv_fl->set_parent (v.get_id());
+    hgv_fl->cm.setType (mplot::ColourMapType::Ocean);
+    hgv_fl->showboundary = true;
+    hgv_fl->setScalarData (&dataf1rrt);
+    hgv_fl->hexVisMode = mplot::HexVisMode::HexInterp;
+    hgv_fl->zScale.null_scaling();
+    hgv_fl->addLabel ("Grid reduced twice", label_pos, tf);
+    hgv_fl->finalize();
+    v.addVisualModel (hgv_fl);
+
+    // Lastly, a dynamic HexGridVisual.
+
+    // Dynamic hexgrid data is a Bessel function
+    std::vector<float> dyn_data(hg1.num(), 0.0f);
+    std::vector<float> r(hg1.num(), 0.0f);
+    float k = 1.0f;
+    auto compute_bessel = [&r, &dyn_data, hg1] (const float k) {
+        for (std::uint32_t hi = 0; hi < hg1.num(); ++hi) {
+            r[hi] = std::sqrt (hg1.d_x[hi] * hg1.d_x[hi] + hg1.d_y[hi] * hg1.d_y[hi]);
+            dyn_data[hi] = std::sin (100.0f * k * r[hi]) / k * r[hi];
+        }
+    };
+
+    // Compute first data state
+    compute_bessel (k);
+
+    // Add a HexGridVisual to display the HexGrid within the mplot::Visual scene
+    offset = {4 * cw, -3 * rh, 0.02f };
+    auto hgv = std::make_unique<mplot::HexGridVisual<float>>(&hg1, offset);
+    hgv->set_parent (v.get_id());
+    hgv->setScalarData (&dyn_data);
+    hgv->showboundary = true;
+    hgv->cm.setType (mplot::ColourMapType::CET_L09);
+    hgv->hexVisMode = mplot::HexVisMode::Triangles;
+    hgv->addLabel ("Dynamic hexgrid\nBessel function\nHexVisMode::Triangles\nColourMapType::CET_L09", label_pos, tf);
+    hgv->finalize();
+    auto hgvp = v.addVisualModel (hgv);
+
+    // Now loop, updating the dynamic hexgrid
+    while (v.readyToFinish() == false) {
+        v.wait (0.08);
+        if (k > 8.0f) { k = 1.0f; }
+        compute_bessel (k);
+        k += 0.1f;
+        if (v.validVisualModel (hgvp) != nullptr) { // Test hgvp is still valid
+            hgvp->updateData (&dyn_data);
+        }
+        v.render();
+    }
 }
diff --git a/examples/screenshots/hexgrid.png b/examples/screenshots/hexgrid.png
index ab27d748..b10acef6 100644
Binary files a/examples/screenshots/hexgrid.png and b/examples/screenshots/hexgrid.png differ
diff --git a/maths b/maths
index 46b2a4d5..97cbc49b 160000
--- a/maths
+++ b/maths
@@ -1 +1 @@
-Subproject commit 46b2a4d5c5007c3928b6916d5b3baef4b5281da9
+Subproject commit 97cbc49b0fa7fe413107e585e170679d31b6eb3a