diff --git a/rogueviz/dandelin.cpp b/rogueviz/dandelin.cpp
new file mode 100644
index 00000000..7a342deb
--- /dev/null
+++ b/rogueviz/dandelin.cpp
@@ -0,0 +1,135 @@
+#include "../hyper.h"
+
+namespace hr {
+namespace dandelin {
+
+int dandelin = 1;
+ld dandelin_h = 1.2;
+ld dandelin_angle = 0;
+
+int dandelin_parts = 7;
+
+eModel mdDandelin;
+
+void add_projection() {
+  int q = isize(mdinf);
+  mdDandelin = eModel(q);
+  eModel p = pmodel;
+  auto mo = mdinf[mdHemisphere];
+  mo.name_hyperbolic = "Dandelin spheres";
+  mo.name_euclidean = "not implemented";
+  mo.name_spherical = "not implemented";
+  mo.flags |= mf::hyper_only;
+  mdinf.push_back(mo);
+  while(isize(extra_projections) < q) extra_projections.emplace_back();
+  extra_projections.emplace_back([p] (shiftpoint& H_orig, hyperpoint& H, hyperpoint& ret) {
+    if(pconf.small_hyperboloid) H = mid(C0, H);
+    ld zl = zlevel(H);
+    ret = H / H[2];
+    ret[2] = sqrt(1 - sqhypot_d(2, ret));
+    ret = ret * (1 + (zl - 1) * ret[2] * pconf.depth_scaling);
+    if(among(dandelin, 2, 4)) {
+      ret[2] -= dandelin_h;
+      }
+    if(dandelin == 3) {
+      ret[2] = - (spin(dandelin_angle) * ret)[0] * sqrt(pow(dandelin_h, 2) - 1);
+      }
+    if(among(dandelin, 4, 5)) {
+      ret[2] *= -1;
+      }
+    swap(ret[1], ret[2]);      
+    ret = pconf.ball() * ret;
+    });
+  pmodel = mdDandelin;
+  }
+
+int get_side(const hyperpoint& H) {
+  if(pmodel != mdDandelin) return 0;
+  if(dandelin == 3) return 1;
+  hyperpoint res;
+  if(dandelin == 2) {
+    dynamicval<int> d(dandelin, 0);
+    applymodel(shiftless(H), res);
+    return res[2] < 0 ? 1 : -1;
+    }
+  if(dandelin == 4) {
+    dynamicval<int> d(dandelin, 5);
+    applymodel(shiftless(H), res);
+    return res[2] < 0 ? 1 : -1;
+    }
+  return 0;
+  }
+
+bool draw_main() {
+  if(pmodel != mdDandelin) return false;
+  if(dandelin != 1) return false;
+  indenter ind(2);
+  dandelin = 4;
+  if(dandelin_parts & 1) hr::draw_main();
+  dandelin = 3;
+  if(dandelin_parts & 2) hr::draw_main();
+  dandelin = 2;
+  if(dandelin_parts & 4) hr::draw_main();
+  dandelin = 1;
+  return true;
+  }
+
+bool draw_boundary(int w) {
+  if(pmodel != mdDandelin) return false;
+  if(w == 1) return true;
+  dynamicval<ld> lw(vid.linewidth, vid.linewidth * vid.multiplier_ring * (svg::in ? svg::divby : 1));
+  color_t lc = ringcolor;
+  color_t fc = modelcolor;
+  
+  auto d = deconstruct_ball();
+
+  auto p = PPR::CIRCLE;
+  for(int s=0; s<5; s++) {
+    queuereset(mdPixel, p);
+    for(int i=0; i<=360; i++) {
+      ld c1 = cos(i * degree);
+      ld s1 = sin(i * degree);
+      if(s == 0)
+        curvepoint(point3(current_display->radius * c1, current_display->radius * (s1 * d.sin_beta - (c1 * cos(dandelin_angle) - s1 * sin(dandelin_angle)) * d.cos_beta * sqrt(pow(dandelin_h,2)-1)), 0));
+      if(s == 1)
+        curvepoint(point3(current_display->radius * c1, current_display->radius * (s1 * d.sin_beta - dandelin_h * d.cos_beta), 0));
+      if(s == 2)
+        curvepoint(point3(current_display->radius * c1, current_display->radius * (s1 * d.sin_beta + dandelin_h * d.cos_beta), 0));
+      auto z = d.cos_beta * s1 >= 0 - 1e-6 ? 1 : abs(d.sin_beta);
+      if(s == 3)
+        curvepoint(point3(current_display->radius * c1, current_display->radius * (-dandelin_h * d.cos_beta + s1 * z), 0));
+      if(s == 4)
+        curvepoint(point3(current_display->radius * c1, current_display->radius * (+dandelin_h * d.cos_beta - s1 * z), 0));
+      /* if(s == 1)
+        curvepoint(point3(current_display->radius * c1, current_display->radius * s1 * (d.cos_beta * s1 >= 0 - 1e-6 ? 1 : abs(d.sin_beta)), 0)); */
+      }
+    queuecurve(shiftless(d.talpha), lc, fc, p);
+    if(s == 4) {
+      curvepoint(point3(current_display->radius * 1, +current_display->radius * dandelin_h * d.cos_beta, 0));
+      curvepoint(point3(current_display->radius * 1, -current_display->radius * dandelin_h * d.cos_beta, 0));
+      queuecurve(shiftless(d.talpha), lc, fc, p);
+      curvepoint(point3(current_display->radius * -1, +current_display->radius * dandelin_h * d.cos_beta, 0));
+      curvepoint(point3(current_display->radius * -1, -current_display->radius * dandelin_h * d.cos_beta, 0));
+      queuecurve(shiftless(d.talpha), lc, fc, p);
+      }
+    queuereset(pmodel, p);
+    }
+
+  return true;
+  }
+
+EX int ad = arg::add3("-dandelin", [] {
+  dandelin = 1;
+  add_projection();
+  addHook(hooks_get_side, 100, get_side);
+  addHook(hooks_draw_main, 100, draw_main);
+  addHook(hooks_draw_boundary, 100, draw_boundary);
+  addHook(hooks_two_sided_model, 100, [] { if(pmodel == mdDandelin) return 1; return 0; });
+  pmodel = mdDandelin;
+  param_f(dandelin_h, "dandelin_h");
+  param_f(dandelin_angle, "dandelin_angle");
+  param_i(dandelin_parts, "dandelin_parts");
+  });
+
+}
+}