diff --git a/classes.cpp b/classes.cpp
index 7e0baed9..d502a7c5 100644
--- a/classes.cpp
+++ b/classes.cpp
@@ -741,7 +741,7 @@ enum eGeometry {
 
 enum eGeometryClass { gcHyperbolic, gcEuclid, gcSphere, gcSolNIH, gcNil, gcProduct, gcSL2 };
 
-enum class eVariation { bitruncated, pure, goldberg, irregular, dual, untruncated, warped, unrectified, subcubes, coxeter, dual_subcubes, bch };
+enum class eVariation { bitruncated, pure, goldberg, irregular, dual, untruncated, warped, unrectified, subcubes, coxeter, dual_subcubes, bch, bch_oct };
 
 typedef int modecode_t;
 
diff --git a/fake.cpp b/fake.cpp
index efd8a729..df1ab115 100644
--- a/fake.cpp
+++ b/fake.cpp
@@ -34,7 +34,7 @@ EX namespace fake {
     if(arcm::in() && PURE) return true;
     if(WDIM == 2) return false;
     if(among(geometry, gBitrunc3)) return false;
-    if(reg3::in() && !among(variation, eVariation::pure, eVariation::subcubes, eVariation::coxeter)) return false;
+    if(reg3::in() && !among(variation, eVariation::pure, eVariation::subcubes, eVariation::coxeter, eVariation::bch_oct)) return false;
     return euc::in() || reg3::in();
     }
   
diff --git a/geom-exp.cpp b/geom-exp.cpp
index 28423459..4cad5e9d 100644
--- a/geom-exp.cpp
+++ b/geom-exp.cpp
@@ -1259,6 +1259,11 @@ int read_geom_args() {
     set_variation(eVariation::bch);
     shift(); reg3::subcube_count = argi();
     }
+  else if(argis("-bch-oct")) {
+    PHASEFROM(2);
+    set_variation(eVariation::bch_oct);
+    shift(); reg3::subcube_count = argi();
+    }
   else if(argis("-coxeter")) {
     PHASEFROM(2);
     set_variation(eVariation::coxeter);
diff --git a/geometry.cpp b/geometry.cpp
index d9640127..64463373 100644
--- a/geometry.cpp
+++ b/geometry.cpp
@@ -530,7 +530,7 @@ static const ld hcrossf7 = 0.620672, hexf7 = 0.378077, tessf7 = 1.090550, hexhex
 EX bool scale_used() { return (shmup::on && geometry == gNormal && BITRUNCATED) ? (cheater || autocheat) : true; }
 
 EX bool is_subcube_based(eVariation var) {
-  return among(var, eVariation::subcubes, eVariation::dual_subcubes, eVariation::bch);
+  return among(var, eVariation::subcubes, eVariation::dual_subcubes, eVariation::bch, eVariation::bch_oct);
   }
 
 EX bool is_reg3_variation(eVariation var) {
diff --git a/graph.cpp b/graph.cpp
index 3b077c89..6d925d20 100644
--- a/graph.cpp
+++ b/graph.cpp
@@ -3781,7 +3781,7 @@ EX int get_darkval(cell *c, int d) {
   const int darkval_kite[12] = {0, 2, 0, 2, 4, 4, 6, 6, 6, 6, 6, 6};
   const int darkval_nil[8] = {6,6,0,3,6,6,0,3};
   const int darkval_nih[11] = {0,2,0,2,4,6,6,6,6,6,6};
-  if(among(variation, eVariation::dual_subcubes, eVariation::bch)) {
+  if(among(variation, eVariation::dual_subcubes, eVariation::bch, eVariation::bch_oct)) {
     int v = reg3::get_face_vertex_count(c, d);
     return v-3;
     }
diff --git a/reg3.cpp b/reg3.cpp
index 41a106d4..1802d61c 100644
--- a/reg3.cpp
+++ b/reg3.cpp
@@ -621,6 +621,49 @@ EX namespace reg3 {
       }
     }
 
+  EX void generate_bch_oct() {
+    if(S7 != 6) throw hr_exception("generate_bch_oct but no cubes");
+    const int sub = subcube_count;
+    if(1) {
+      auto vx = abs(cgi.heptshape->faces[0][0][0]);
+      auto vz = abs(cgi.heptshape->faces[0][0][3]);
+      array<int, 3> co;
+      // vx = 1; vz = 0;
+      for(co[0]=-sub; co[0]<sub; co[0]++)
+      for(co[1]=-sub; co[1]<sub; co[1]++)
+      for(co[2]=-sub; co[2]<sub; co[2]++) {
+        auto co1 = co;
+        array<ld, 3> sgn = {1,1,1};
+        if((co[1] ^ co[0]) & 1) co1[1]++, sgn[1] = -1;
+        if((co[2] ^ co[0]) & 1) co1[2]++, sgn[2] = -1;
+
+        hyperpoint ctr = Hypc;
+        ctr[3] = vz * sub;
+        
+        auto pt = [&] (int m, ld x0, ld x1, ld x2) {
+          hyperpoint res = ctr;
+          auto x = make_array(x0, x1, x2);
+          for(int i=0; i<3; i++)
+            res[i] = vx * (co1[i] + x[(m+i)%3] * sgn[i]);
+          return res;
+          };
+
+        for(int it=0; it<2; it++) {        
+          cgi.subshapes.emplace_back();
+          auto &ss = cgi.subshapes.back();
+          for(int m=0; m<3; m++) {
+            ss.faces.push_back({pt(m,0,0,0), pt(m,1,0,0), pt(m,1,0,.5), pt(m,.5,0,1), pt(m,0,0,1)});
+            ss.faces.push_back({pt(m,1,0,0), pt(m,1,0,.5), pt(m,1,.5,0) });
+            }
+          ss.faces.push_back({pt(0,1,0,.5), pt(0,1,.5,0), pt(0,.5,1,0), pt(0,0,1,.5), pt(0,0,.5,1), pt(0,.5,0,1)});
+          for(int d=0; d<3; d++)
+            co1[d] += sgn[d], sgn[d] *= -1;
+          println(hlog, ss.faces);
+          }
+        }
+      }
+    }
+
   EX void generate_subcells() {
     
     switch(variation) {
@@ -636,6 +679,10 @@ EX namespace reg3 {
         generate_special_subcubes(true);
         break;
       
+      case eVariation::bch_oct:
+        generate_bch_oct();
+        break;
+      
       case eVariation::coxeter:
         generate_coxeter(coxeter_param);
         break;