diff --git a/rogueviz-pentagonal.cpp b/rogueviz-pentagonal.cpp
new file mode 100644
index 00000000..518cd5fb
--- /dev/null
+++ b/rogueviz-pentagonal.cpp
@@ -0,0 +1,345 @@
+namespace rogueviz {
+
+namespace pentagonal {
+transmatrix ts[3];
+
+using namespace hyperpoint_vec;
+
+hyperpoint facingdir(array<hyperpoint,3>& a) {
+  hyperpoint tmp = (a[1]-a[0]) ^ (a[2]-a[0]);
+  tmp /= sqrt(tmp|tmp);
+  return tmp;
+  }
+
+vector<pair<ld, transmatrix>> sideangles;
+
+cell *p0, *t0, *t1, *t2, *cc;
+
+bool snubon;
+
+hyperpoint cor;
+
+void kframe() {
+  if(snubon) {
+  queuestr(gmatrix[p0], 0.6, "P0", 0xFFFFFF, 1);
+  queuestr(gmatrix[cc], 0.6, "C", 0xFFFFFF, 1);
+  queuestr(gmatrix[t0], 0.6, "T0", 0xFFFFFF, 1);
+  queuestr(gmatrix[t1], 0.6, "T1", 0xFFFFFF, 1);
+  queuestr(gmatrix[t2], 0.6, "T2", 0xFFFFFF, 1);
+  }}
+
+hyperpoint xts0;
+array<hyperpoint, 3> mts;
+
+rug::rugpoint *pt(hyperpoint h, hyperpoint c, int id) {
+  auto r = rug::addRugpoint(C0, -1);
+  r->flat = h;
+  r->x1 = (1 + c[0]) / 16 + (id/8) / 8.;
+  r->y1 = (1 + c[1]) / 16 + (id%8) / 8.;
+  r->valid = true;
+  return r;
+  }
+
+hyperpoint inplane(array<hyperpoint, 3>& a, hyperpoint line) {
+  hyperpoint mu = (a[1]-a[0]) ^ (a[2]-a[0]);
+  // (a[0] | mu) == (line * z | mu)
+  return line * (a[0] | mu) / (line | mu);
+  }
+
+transmatrix matrix2;
+
+#if CAP_TEXTURE
+bool need_texture = true;
+texture::texture_data tdata; // = texture::config.data;
+#endif
+
+int global_v, global_w;
+
+void make_texture() {
+  #if CAP_TEXTURE
+  rug::renderonce = true;
+  need_texture = false;
+  tdata.whitetexture();
+  int tw = tdata.twidth;
+  printf("tw = %d\n", tw);
+  int fw = tw / 4;
+  auto pix = [&] (int k, int x, int y) -> unsigned& {
+    return tdata.texture_pixels[y * tw + x + (k&3) * fw + (k>>2) * fw * tw];
+    };
+  for(int y=0; y<tw; y++)
+  for(int x=0; x<tw; x++) 
+  for(int p=0; p<3; p++) {
+    int ax = x / (tw/8);
+    int ay = y / (tw/8);
+    int bx = x % (tw/8);
+    int by = y % (tw/8);
+    int id = ax * 8 + ay;
+    hyperpoint h = sideangles[id % isize(sideangles)].second * xts0;
+    if(!sphere) {
+      hyperpoint ehs[7] = {hpxyz(0,-1,-1), hpxyz(0,0,-1), hpxyz(-1,0,-1), hpxyz(-1,0,0), hpxyz(-1,-1,0), hpxyz(0,-1,0), hpxyz(0,-1,-1)};
+      ld idx = (id % global_v) * 6. / global_v;
+      h = ehs[int(idx)] * (1-(idx-int(idx))) + ehs[int(idx)+1] * (idx-int(idx));
+      }
+    ld hyp = hypot(bx-tw/16, by-tw/16) / (tw/16);
+    if(hyp > 1) hyp = 1;
+    part(pix(0,x,y), p) = 255 * (1 * hyp + (0.5 + h[p]/2) * (1-hyp));
+    }
+  
+  tdata.loadTextureGL();
+
+  rug::alternate_texture = tdata.textureid;
+  #endif
+  }
+
+void create_model();
+
+void run_snub(int v, int w) {
+  snubon = false;
+  global_v = v; global_w = w;
+  printf("set geometry\n");
+  stop_game(); autocheat = true; 
+  int bonus;  
+  if(w == 4 && v == 4) bonus = 12;
+  else if(w == 4 && v == 5) bonus = 7;
+  else if(w == 4 && v == 6) bonus = 4;
+  else if(w == 3 && v == 6) bonus = 12;
+  else if(w == 3 && v == 7) bonus = 8;
+  else if(w == 3 && v == 8) bonus = 7;
+  else if(w == 3 && v == 9) bonus = 6;
+  else bonus = 0;
+  gamerange_bonus = genrange_bonus = sightrange_bonus = bonus;
+  set_geometry(gArchimedean);
+  set_variation(eVariation::pure);
+  arcm::current.parse("("+its(v)+",3," + its(w) + ",3,3) (2,3)(1,0)(4)");
+  specialland = laCanvas;
+  patterns::whichCanvas = 'A';
+  // vid.wallmode = 1;
+  need_reset_geometry = true;
+  printf("start game\n");
+  printf("distlimit = %d\n", base_distlimit);
+  precalc();
+  printf("distlimit = %d\n", base_distlimit);
+  start_game();
+  printf("ok\n");
+  printf("allcells = %d\n", isize(currentmap->allcells()));
+  
+  sideangles.clear();
+  printf("gamerange = %d\n", gamerange());
+  printf("genrange = %d\n", getDistLimit() + genrange_bonus);
+  setdist(cwt.at, 7 - getDistLimit() - genrange_bonus, NULL);
+  bfs();
+  
+  drawthemap();
+  
+  if(euclid || sphere) for(cell *c: currentmap->allcells())
+    gmatrix[c] = arcm::archimedean_gmatrix[c->master].second;
+
+  cellwalker cw(currentmap->gamestart(), 0);
+  p0 = cw.at;
+  t0 = (cw - 1 + wstep).at;
+  t1 = (cw + wstep).at;
+  t2 = (cw + wstep + 1 + wstep - 1).at;
+  // p1 = (cw + wstep + 1 + wstep -1 + wstep).at;
+  cc = (cw - 1 + wstep - 1 + wstep).at;
+  
+  transmatrix rel = inverse(gmatrix[p0]);
+  
+  ts[0] = rel * gmatrix[t0] * ddspin(t0, (cw - 1 + wstep).spin);
+  ts[1] = rel * gmatrix[t1];
+  ts[2] = rel * gmatrix[t2] * ddspin(t2, (cw + wstep + 1 + wstep - 1).spin);
+  
+  matrix2 = ts[2] * inverse(ts[0]);
+  
+  for(int i=0; i<3; i++) mts[i] = ts[i] * C0;
+  hyperpoint f = facingdir(mts);
+
+  for(cell *c: currentmap->allcells()) {
+    int id = arcm::id_of(c->master);
+    if(among(id, 0, 1)) for(int d=0; d<v; d++) {
+      transmatrix T = rel * ggmatrix(c) * spin(2*M_PI*d/v);
+      array<hyperpoint,3> hts;
+      for(int i=0; i<3; i++) 
+        hts[i] = T * ts[i] * C0;
+      // for(int i=0; i<3; i++) printf("%s ", display(hts[i])); 
+      hyperpoint f1 = facingdir(hts);
+      
+      ld scalar = (f|f1);
+      ld alpha = (M_PI - acos(scalar)) * 180 / M_PI;
+      sideangles.emplace_back(alpha, T);
+      }
+    }
+    
+  vector<double> sav;
+  for(auto p: sideangles) sav.push_back(p.first);
+  sort(sav.begin(), sav.end());
+  
+  printf("sideangles "); for(int i=0; i<3; i++) printf("%lf ", double(sav[i])); printf("\n");
+  
+  xts0 = tC0(ts[0]);
+  
+  printf("original %s\n", display(xts0));
+  
+  cor = rel * gmatrix[cc] * C0;
+
+  rug::reopen();
+  for(auto p: rug::points) p->valid = true;
+  rug::good_shape = true;  
+
+  make_texture();
+  
+  create_model();
+  printf("points = %d tris = %d side = %d\n", isize(rug::points), isize(rug::triangles), isize(sideangles));
+  rug::model_distance = euclid ? 4 : 2;
+  rug::rug_perspective = hyperbolic;
+  showstartmenu = false;
+  snubon = true;
+  rug::invert_depth = hyperbolic;
+  }
+
+void create_model() {
+
+  int v = global_v;
+  rug::clear_model(); 
+  ld x = (mousex - vid.xcenter + .0) / vid.xres;
+  ld y = (mousey - vid.ycenter + .0) / vid.yres;
+  
+  ld alpha = atan2(y, x);
+  ld h = hypot(x, y);
+
+  hyperpoint chk = ts[0] * xspinpush0(alpha, h);
+
+  mts[0] = chk;
+  mts[1] = spin(-2*M_PI/v) * chk;
+  mts[2] = matrix2 * chk;
+
+  hyperpoint c[5];
+  for(int i=0; i<5; i++)
+    c[i] = hpxy(sin(2 * i * M_PI/5), cos(2 * i * M_PI/5));
+    
+  hyperpoint tria[5];
+  tria[0] = mts[0];
+  tria[1] = inplane(mts, C0);
+  tria[2] = mts[1];
+  tria[3] = mts[2];
+  tria[4] = inplane(mts, cor);
+  
+  hyperpoint ctr = Hypc;
+  for(int i=0; i<5; i++) ctr += tria[i];
+  ctr = inplane(mts, ctr);
+  
+  transmatrix tester = spin(1.1) * xpush(1);
+  
+  int idh = 0;
+  
+  for(hyperpoint h: {ctr, tria[0], tria[1], tria[2], tria[3], tria[4], ctr}) {
+    int good1 = 0, good2 = 0;
+    // printf("%d: ", idh);
+    for(int i=0; i<5; i++) {
+      array<hyperpoint, 3> testplane;
+      testplane[0] = tester * h;
+      testplane[1] = tester * tria[i];
+      testplane[2] = tester * tria[(i+1)%5];
+      hyperpoint f = facingdir(testplane);
+      // printf("%lf ", f[0]);
+      if(f[0] > -1e-6 || isnan(f[0])) good1++;
+      if(f[0] < +1e-6 || isnan(f[0])) good2++;
+      }
+    // printf("\n");
+    if(good1 == 5 || good2 == 5) {ctr = h; break; }
+    idh++;
+    }
+  
+  // printf("idh = %d\n", idh);
+
+  transmatrix t = hyperbolic ? rotmatrix(M_PI, 0, 2) * xpush(sin(ticks * M_PI / 8000.)) : rotmatrix(ticks * M_PI / 8000., 0, 2);
+  
+  hyperpoint hs = hyperbolic ? hpxyz(0,0,-1) : hpxyz(0,0,0);
+  
+  if(euclid) t = Id;
+  
+  int id = 0;
+  for(auto& p: sideangles) {
+    auto& T = p.second;
+    array<rug::rugpoint*,5> hts;
+    auto cpt = pt(hs + t * T * ctr, C0, id);
+
+    for(int s=0; s<5; s++) 
+      hts[s] = pt(hs + t * T * tria[s], c[s], id);
+
+    for(int s=0; s<5; s++) 
+      rug::addTriangle(cpt, hts[s], hts[(s+1)%5]);
+      
+    id++;
+    if(!sphere) id %= global_v;
+    }
+  
+  }
+
+#if CAP_COMMANDLINE  
+int readArgs() {
+  using namespace arg;
+           
+  if(0) ;
+  else if(argis("-snub")) {
+    PHASE(3);
+    shift();
+    run_snub(argi(), 3);
+    }
+  else if(argis("-snub4")) {
+    PHASE(3);
+    shift();
+    run_snub(argi(), 4);
+    }
+  else return 1;
+  return 0;
+  }
+#endif
+
+bool frame() { 
+  if(snubon && rug::rugged) {
+    create_model();
+    nomenukey = true;
+    displaychr(vid.xcenter, vid.ycenter, 0, 10, 'X', 0xFFFFFF);
+    clearMessages();
+    nohelp = true;
+    playerfound = true;
+    }
+  return true;
+  }
+
+bool handleKey(int sym, int uni) {
+  if(snubon) {
+    if(among(uni, '3', '4', '5', '6', '7', '8', '9'))  {
+      run_snub(uni - '0', 3);
+      return true;
+      }
+    if(among(uni, '#', '$', '%', '&', '^'))  {
+      if(uni == '^') uni = '&';
+      run_snub(uni - 32, 4);
+      return true;
+      }
+    if(uni == 'a') {
+      rug::close();
+      mapeditor::drawplayer = false;
+      return true;
+      }
+    if(uni == 's' && rug::rugged) {
+      stereo::fov += 30;
+      if(stereo::fov >= 180) stereo::fov = 60;
+      }
+    if(uni == 'i' && rug::rugged) {
+      rug::invert_depth = !rug::invert_depth;
+      return true;
+      }
+    }
+  return false;
+  }
+
+
+auto xhook = addHook(hooks_args, 100, readArgs)
++ addHook(hooks_handleKey, 0, handleKey)
++ addHook(hooks_prestats, 0, frame)
++ addHook(clearmemory, 40, [] () { snubon = false; } );
+ 
+}
+}
diff --git a/rogueviz.cpp b/rogueviz.cpp
index 38efc6d2..6249bd22 100644
--- a/rogueviz.cpp
+++ b/rogueviz.cpp
@@ -2022,6 +2022,23 @@ slide rvslides[] = {
           }
         }
       }},
+    {"Pentagonal Exploration", 62, LEGAL_NONE | QUICKGEO,
+     "Pentagonal Exploration explained at: http://www.roguetemple.com/z/sims/snub/\n\n"
+     "Move the mouse nearer and further away from the X.\n\n"
+     "Press 3 4 5 6 7 8 9 shift+4 shift+5 shift+6 to change the geometry.",
+     
+    [] (presmode mode) {
+      if(mode == 1) {
+        pentagonal::run_snub(5, 3);
+        }
+      if(mode == 3) {
+        printf("stopping\n");
+        set_geometry(gNormal);
+        set_variation(eVariation::bitruncated);
+        rug::close();
+        start_game();
+        }
+      }},
   {"THE END", 99, LEGAL_ANY | FINALSLIDE,
     "Press '5' to leave the presentation.",
     [] (presmode mode) {
@@ -2118,4 +2135,5 @@ auto hooks  =
 #include "rogueviz-staircase.cpp"
 #include "rogueviz-banachtarski.cpp"
 #include "rogueviz-video.cpp"
+#include "rogueviz-pentagonal.cpp"
 
diff --git a/rogueviz.h b/rogueviz.h
index c3ed9c05..9738697f 100644
--- a/rogueviz.h
+++ b/rogueviz.h
@@ -96,5 +96,9 @@ namespace rogueviz {
     extern bool bmap;
     extern void init_bantar_map();
     }
+  
+  namespace pentagonal {
+    void run_snub(int v, int w);
+    }
 }