diff --git a/arbitrile.cpp b/arbitrile.cpp
index bb00956c..bc5974b0 100644
--- a/arbitrile.cpp
+++ b/arbitrile.cpp
@@ -1603,8 +1603,7 @@ struct hrmap_arbi : hrmap {
     
     transmatrix T = p.second * adj(h, d);
     
-    transmatrix U;
-    bm.rebase(alt, T, U);
+    bm.rebase(alt, T);
     fixmatrix(T);
 
     for(auto& p2: bm.what_at[alt]) if(id_of(p2.first) == co.sid) {
diff --git a/archimedean.cpp b/archimedean.cpp
index f4f403b3..5e4e1088 100644
--- a/archimedean.cpp
+++ b/archimedean.cpp
@@ -657,12 +657,11 @@ struct hrmap_archimedean : hrmap {
 
     auto& p1 = bm.where[h];
 
-    heptagon *alt = p1.first; auto alt0 = alt;
+    heptagon *alt = p1.first; // auto alt0 = alt;
 
     transmatrix T = p1.second * spin(-t1.first) * lxpush(t1.second);
-    transmatrix U = Id;
 
-    bm.rebase(alt, T, U);
+    bm.rebase(alt, T);
 
     if(debug_geometry) println(hlog, "look for: ", alt, " / ", kz(T * C0));
 
@@ -675,17 +674,19 @@ struct hrmap_archimedean : hrmap {
         if(debug_geometry) println(hlog, "compare: ", kz(T1 * lxpush0(1)), ":: ", kz(p2.second * lxpush0(1)));
         if(same_point_may_warn(T1 * lxpush0(1), p2.second * lxpush0(1))) {
         
+          #if 0
           // T1 = p2.second
           // T * spin(pi+t2.first) == p2.second
           // p1.second * spinm(-t1.first) * lxpush(t1.second) * spin(pi+t2.first) == p2.second
           
           // bring p1 and p2 closer, to prevent floating point errors
-          if(hyperbolic && false) {
+          if(hyperbolic) {
             fixup_matrix(p1.second, U * p2.second * spin(-M_PI - t2.first) * lxpush(-t1.second) * spin(t1.first), 0.25);
             fixup_matrix(p2.second, T1, 0.25);
             for(auto& z: bm.what_at[alt0]) if(z.first == h) z.second = p1.second;
             bm.where[p2.first].second = p2.second;
             }
+          #endif
   
           while(skip_digons(hs, -1)) hs--;
           connectHeptagons(hi, hs);
diff --git a/backed-map.cpp b/backed-map.cpp
index 26224b12..fee3da6f 100644
--- a/backed-map.cpp
+++ b/backed-map.cpp
@@ -15,7 +15,7 @@ struct backed_map {
 
   void initialize(heptagon *origin);
   void assign(heptagon *actual, heptagon *backer, transmatrix T);
-  void rebase(heptagon*& backer, transmatrix& T, transmatrix& U);
+  void rebase(heptagon*& backer, transmatrix& T);
   void handle_precision_errors(heptagon *actual);
 
   geometry_information *alt_cgip[2];
@@ -69,16 +69,14 @@ void backed_map::assign(heptagon *actual, heptagon *backer, transmatrix T) {
   what_at[backer].emplace_back(actual, T);
   }
 
-void backed_map::rebase(heptagon*& backer, transmatrix& T, transmatrix& U) {
+void backed_map::rebase(heptagon*& backer, transmatrix& T) {
   if(mhyperbolic) {
     dynamicval<int> uc(cgip->use_count, cgip->use_count+1);
     dynamicval<eGeometry> g(geometry, gNormal);
     dynamicval<eVariation> gv(variation, eVariation::pure);
     dynamicval<geometry_information*> gi(cgip, find_alt_cgip());
     dynamicval<hrmap*> cm(currentmap, current_altmap);
-    U = T;
     current_altmap->virtualRebase(backer, T);
-    U = U * iso_inverse(T);
     }
   if(euclid) {
     /* hash the rough coordinates as heptagon* alt */
@@ -124,8 +122,7 @@ void backed_map::handle_precision_errors(heptagon *h) {
           auto p2 = p1;
           p2.second = T;
 
-          transmatrix T0 = Id;
-          rebase(p2.first, p2.second, T0);
+          rebase(p2.first, p2.second);
 
           if(first) {
             if(where.count(h2)) {