diff --git a/rogueviz/sag.cpp b/rogueviz/sag.cpp
index 350c5348..86c849b6 100644
--- a/rogueviz/sag.cpp
+++ b/rogueviz/sag.cpp
@@ -22,100 +22,84 @@ namespace sag {
   const char *sagmodes[3] = {"off", "HC", "SA"};
   
   ld temperature = -4;
-  const int INSNAKE = 117;
-  int numsnake;
   const char *loadfname;
   
-  #define MAXSNAKETAB 1000
-  int sdist[MAXSNAKETAB][MAXSNAKETAB];
-  int insnaketab = 0;
+  int vizsa_start;
+  int vizsa_len;
+  
+  /** all the SAG cells */
+  vector<cell*> sagcells;
 
-  vector<cell*> snakecells;
-  vector<int> snakefirst, snakelast;
-  vector<int> snakenode;
-  vector<int> snakeid;
-  vector<int> lpbak;
-  vector<int> wpbak;
-  
-  bool snake_enabled;
+  /** table of distances between SAG cells */
+  vector<vector<int>> sagdist;
 
-  void setsnake(cellwalker& cw, int i) {
-    lpbak[i] = cw.at->landparam;
-    wpbak[i] = cw.at->wparam;
-    cw.at->landparam = i; cw.at->wparam = INSNAKE;
-    // cw.at->monst = moWormtail; cw.at->mondir = cw.spin;
-    snakecells[i] = cw.at;
-    }
+  /** what node is on sagcells[i] */
+  vector<int> sagnode;
+
+  /** node i is on sagcells[sagid[i]] */
+  vector<int> sagid;
+
+  /** sagcells[ids[c]]] == c */
+  map<cell*, int> ids;
+
+  /** if i in neighbors[j], sagcells[i] is a neighbor of sagcells[j] */
+  vector<vector<int>> neighbors;
   
-  void snakeswitch() { 
-    for(int i=0; i<numsnake; i++) {
-      cell *c = snakecells[i];
-      int x;
-      x = lpbak[i]; lpbak[i] = c->landparam; c->landparam = x;
-      x = wpbak[i]; wpbak[i] = c->wparam; c->wparam = x;
-      }
-    snake_enabled = !snake_enabled;
-    }
-    
-  void enable_snake() { if(!snake_enabled) snakeswitch(); }
-    
-  void disable_snake() { if(snake_enabled) snakeswitch(); }
-    
-  int snakedist(int i, int j) {
-    if(i < insnaketab && j < insnaketab) return sdist[i][j];
-    if(closed_manifold) return celldistance(snakecells[i], snakecells[j]);
-    int i0 = i, i1 = i, j0 = j, j1 = j;
-    int cost = 0;
-    // intersect
-    while(true) {
-      if(j0 > i1+1) { j0 = snakefirst[j0], j1 = snakelast[j1]; cost++; }
-      else if(i0 > j1+1) { i0 = snakefirst[i0], i1 = snakelast[i1]; cost++; }
-      else if(j1+1 == i0) return cost+1;
-      else if(i1+1 == j0) return cost+1;
-      else return cost;
+  void compute_dists() {
+    int N = isize(sagcells);
+
+    neighbors.clear();
+    neighbors.resize(N);
+
+    for(int i=0; i<N; i++)
+      for(cell *c1: adj_minefield_cells(sagcells[i]))
+        if(ids.count(c1)) neighbors[i].push_back(ids[c1]);
+
+    sagdist.clear();
+    sagdist.resize(N);
+    for(int i=0; i<N; i++) {
+      auto &sdi = sagdist[i];
+      sdi.resize(N, N);
+      vector<int> q;
+      auto visit = [&] (int j, int dist) { if(sdi[j] < N) return; sdi[j] = dist; q.push_back(j); };
+      visit(i, 0);
+      for(int j=0; j<isize(q); j++) for(int k: neighbors[q[j]]) visit(k, sdi[q[j]]+1);
       }
     }
-  
-  void initSnake(int n) {
-    if(closed_or_bounded) n = isize(currentmap->allcells());
-    numsnake = n;
-    snakecells.resize(numsnake);
-    snakefirst.resize(numsnake);
-    snakelast.resize(numsnake);
-    snakenode.resize(numsnake);
-    lpbak.resize(numsnake);
-    wpbak.resize(numsnake);
-    if(closed_or_bounded) {
-      for(int i=0; i<n; i++) {
-        cellwalker cw(currentmap->allcells()[i], 0);
-        setsnake(cw, i);
-        }
-      }
-    else {
-      cellwalker cw = cwt;
-      setsnake(cw, 0);
+
+  bool legacy;
+
+  /* legacy method */
+  void init_snake(int n) {
+    sagcells.clear();
+    ids.clear();
+
+    auto enlist = [&] (cellwalker cw) {
+      ids[cw.at] = isize(sagcells);
+      sagcells.push_back(cw.at);
+      };
+
+    cellwalker cw = cwt;
+    enlist(cw);
+    cw += wstep;
+    enlist(cw);
+    for(int i=2; i<n; i++) {
       cw += wstep;
-      setsnake(cw, 1);
-      for(int i=2; i<=numsnake; i++) {
-        if(i == numsnake && sphere) break;
-        cw += wstep;
-        snakefirst[i-1] = cw.at->landparam;
-        while(cw.at->wparam == INSNAKE) {
-          snakelast[i-1] = cw.at->landparam;
-          cw = cw + wstep + 1 + wstep;
-          }
-        if(i == numsnake) break;
-        setsnake(cw, i); cw += 1;
+      while(ids.count(cw.at)) {
+        cw = cw + wstep + 1 + wstep;
         }
+      enlist(cw); cw += 1;
       }
-    int stab = min(numsnake, MAXSNAKETAB);
-    for(int i=0; i<stab; i++)
-    for(int j=0; j<stab; j++)
-      sdist[i][j] = snakedist(i,j);
-    insnaketab = stab;
-    snake_enabled = true;
     }
-  
+
+  void init_sag_cells() {
+    sagcells = currentmap->allcells();
+    int N = isize(sagcells);
+
+    ids.clear();
+    for(int i=0; i<N; i++) ids[sagcells[i]] = i;
+    }
+
   ld hub_penalty;
   string hub_filename;
   vector<int> hubval;
@@ -127,27 +111,17 @@ namespace sag {
     for(int j=0; j<isize(vd.edges); j++) {
       edgeinfo *ei = vd.edges[j].second;
       int t2 = vd.edges[j].first;
-      if(snakeid[t2] != -1) cost += snakedist(sid, snakeid[t2]) * ei->weight2;
+      if(sagid[t2] != -1) cost += sagdist[sid][sagid[t2]] * ei->weight2;
       }
     
     if(!hubval.empty()) {
-      cell *c = snakecells[sid];
-      for(int i=0; i<c->type; i++) {
-        cell *c2 = c->move(i);
-        if(c2 && c2->wparam == INSNAKE) {
-          int vid2 = snakenode[c2->landparam];
-          if(vid2 >= 0 && (hubval[vid] & hubval[snakenode[c2->landparam]]) == 0)
-            cost += hub_penalty;
-          }
+      for(auto sid2: neighbors[sid]) {
+        int vid2 = sagnode[sid2];
+        if(vid2 >= 0 && (hubval[vid] & hubval[vid]) == 0)
+          cost += hub_penalty;
         }
       }
     
-    /* cell *c = snakecells[id];
-    for(int i=0; i<c->type; i++) {
-      cell *c2 = c->move(i);
-      if(c2 && c2->wparam == INSNAKE && snakenode[c2->landparam] >= 0)
-        cost += 100;
-      } */
     return cost;
     }
   
@@ -156,7 +130,6 @@ namespace sag {
   bool infullsa;
   
   double cost;
-  int N;
 
   vector<double> chgs;  
   
@@ -177,91 +150,62 @@ namespace sag {
     }
 
   void saiter() {
-    aiter:
-
-    int t1 = hrand(N);
-    int sid1 = snakeid[t1];
+    int DN = isize(sagid);
+    int t1 = hrand(DN);
+    int sid1 = sagid[t1];
     
     int sid2;
     
-    int s = hrand(6);
-    
-    if(s == 3) s = 2;
-    if(s == 4) s = 5;
-    
-    if((sagpar&1) && (s == 2 || s == 3 || s == 4)) return;
-    
-    if(s == 5) sid2 = hrand(numsnake);
+    int s = hrand(4)+1;
     
+    if(s == 4) sid2 = hrand(isize(sagcells));
     else {
-      cell *c;
-      if(s>=2 && isize(vdata[t1].edges)) c = snakecells[snakeid[hrand(isize(vdata[t1].edges))]];
-      else c = snakecells[sid1];
-      
-      int it = s<2 ? (s+1) : s-2;
-      for(int ii=0; ii<it; ii++) {
-        int d = hrand(c->type);
-        c = c->move(d);
-        if(!c) goto aiter;
-        if(c->wparam != INSNAKE) goto aiter;
-        }
-      sid2 = c->landparam;
+      sid2 = sid1;
+      for(int ii=0; ii<s; ii++) sid2 = hrand_elt(neighbors[sid2]);
       }
-    int t2 = snakenode[sid2];
+    int t2 = sagnode[sid2];
     
-    snakenode[sid1] = -1; snakeid[t1] = -1;
-    snakenode[sid2] = -1; if(t2 >= 0) snakeid[t2] = -1;
+    sagnode[sid1] = -1; sagid[t1] = -1;
+    sagnode[sid2] = -1; if(t2 >= 0) sagid[t2] = -1;
     
     double change = 
       costat(t1,sid2) + costat(t2,sid1) - costat(t1,sid1) - costat(t2,sid2);
-
-    snakenode[sid1] = t1; snakeid[t1] = sid1;
-    snakenode[sid2] = t2; if(t2 >= 0) snakeid[t2] = sid2;
     
-    if(change < 0) chgs.push_back(-change);
-      
+    sagnode[sid1] = t1; sagid[t1] = sid1;
+    sagnode[sid2] = t2; if(t2 >= 0) sagid[t2] = sid2;
+    
     if(change > 0 && (sagmode == sagHC || !chance(exp(-change * exp(-temperature))))) return;
 
-    snakenode[sid1] = t2; snakenode[sid2] = t1;
-    snakeid[t1] = sid2; if(t2 >= 0) snakeid[t2] = sid1;
-    if(vdata[t1].m) vdata[t1].m->base = snakecells[sid2];
-    if(t2 >= 0 && vdata[t2].m) vdata[t2].m->base = snakecells[sid1];
+    sagnode[sid1] = t2; sagnode[sid2] = t1;
+    sagid[t1] = sid2; if(t2 >= 0) sagid[t2] = sid1;
     cost += 2*change;
-    
-    if(t1 >= 0) forgetedges(t1);
-    if(t2 >= 0) forgetedges(t2);
     }
   
-  void organize() {
-    for(int i=0; i<numsnake; i++) snakenode[i] = -1;
-    vector<int> freenodes;
-    for(int i=0; i<N; i++) 
-      if(snakeid[i] != -1)
-        snakenode[snakeid[i]] = i;
-
-    for(int i=0; i<N; i++) 
-      if(snakeid[i] != -1)
-        if(snakenode[snakeid[i]] != i)
-          snakeid[i] = -1;
-
-    for(int i=0; i<numsnake; i++) 
-      if(snakenode[i] == -1)
-        freenodes.push_back(i);
-    
-    int j = 0;
-    for(int i=0; i<N; i++) 
-      if(snakeid[i] == -1) {
-        snakeid[i] = freenodes[j];
-        snakenode[freenodes[j]] = i;
-        j++;
-        }
-    cost = 0; for(int i=0; i<N; i++) cost += costat(i, i);
+  void create_sagnode() {
+    sagnode.clear();
+    sagnode.resize(isize(sagcells), -1);
+    int DN = isize(sagid);
+    for(int i=0; i<DN; i++)
+      sagnode[sagid[i]] = i;
+    cost = 0;
+    for(int i=0; i<DN; i++)
+      cost += costat(i, sagid[i]);
     }
   
-  void loadsnake(const string& fname) {
+  void reassign() {
+    int DN = isize(sagid);
+    for(int i=0; i<DN; i++) {
+      vdata[i].m->base = sagcells[sag::sagid[i]];
+      forgetedges(i);
+      }
+    shmup::fixStorage();
+    }
+
+  void load_sag_solution(const string& fname) {
     printf("Loading the sag from: %s\n", fname.c_str());
     FILE *sf = fopen(fname.c_str(), "rt");
     if(!sf) { printf("Failed to open file.\n"); exit(1); }
+    int SN = isize(sagcells);
     if(sf) while(true) {
       string lab;
       while(true) {
@@ -273,33 +217,24 @@ namespace sag {
         }
       int sid = -1;
       int err = fscanf(sf, "%d", &sid);
-      if(sid < 0 || sid >= numsnake || err < 1) sid = -1;
+      if(sid < 0 || sid >= SN || err < 1) sid = -1;
       if(!labeler.count(lab)) {
         printf("unknown vertex: %s\n", lab.c_str());
         }
       else {
         int id = getid(lab);
-        snakeid[id] = sid;
+        sagid[id] = sid;
         }
       }
     afterload: 
     if(sf) fclose(sf);
 
-    organize();
-    for(int i=0; i<N; i++) {
-      if(vdata[i].m) vdata[i].m->base = snakecells[sag::snakeid[i]];
-      forgetedges(i);
-      }
-
-    shmup::fixStorage();
+    create_sagnode();
+    reassign();
     }
   
   vector<edgeinfo> sagedges;
   
-  /* bool totcmp(int i, int j) {
-    return totwei[i] > totwei[j];
-    } */
-  
   int ipturn = 100;
   int numiter = 0;
   
@@ -308,7 +243,6 @@ namespace sag {
   
   void dofullsa(int satime) {
     sagmode = sagSA;
-    enable_snake();
     int t1 = SDL_GetTicks();
     
     while(true) {
@@ -321,48 +255,48 @@ namespace sag {
         numiter++;
         sag::saiter();
         }
-      DEBB(DF_LOG, (format("it %8d temp %6.4f [1/e at %13.6f] cost = %f ", 
+      
+      print(hlog, format("it %8d temp %6.4f [1/e at %13.6f] cost = %f ", 
         numiter, double(sag::temperature), (double) exp(sag::temperature),
-        double(sag::cost))));
+        double(sag::cost)));
       
       sort(chgs.begin(), chgs.end());
       int cc = chgs.size() - 1;
-      DEBB(DF_LOG, (format("%9.4f .. %9.4f .. %9.4f .. %9.4f .. %9.4f\n", 
-        double(chgs[0]), double(chgs[cc/4]), double(chgs[cc/2]), double(chgs[cc*3/4]), double(chgs[cc]))));
-      fflush(stdout);
+      println(hlog, format("%9.4f .. %9.4f .. %9.4f .. %9.4f .. %9.4f", 
+        double(chgs[0]), double(chgs[cc/4]), double(chgs[cc/2]), double(chgs[cc*3/4]), double(chgs[cc])));
       }
     
     temperature = -5;
-    disable_snake();
     sagmode = sagOff;
+    reassign();
     }
 
   void iterate() {
     if(!sagmode) return;
     int t1 = SDL_GetTicks();
-    enable_snake();
     for(int i=0; i<ipturn; i++) {
       numiter++;
       sag::saiter();
       }
-    disable_snake();
     int t2 = SDL_GetTicks();
     int t = t2 - t1;
     if(t < 50) ipturn *= 2;
     else if(t > 200) ipturn /= 2;
     else ipturn = ipturn * 100 / t;
-    DEBB(DF_LOG, ("it %8d temp %6.4f [2:%8.6f,10:%8.6f,50:%8.6f] cost = %f\n", 
+    print(hlog, format("it %8d temp %6.4f [2:%8.6f,10:%8.6f,50:%8.6f] cost = %f\n", 
       numiter, double(sag::temperature), 
       (double) exp(-2 * exp(-sag::temperature)),
       (double) exp(-10 * exp(-sag::temperature)),
       (double) exp(-50 * exp(-sag::temperature)),
       (double) sag::cost));
+
+    reassign();
     }
   
-  void savesnake(const string& fname) {
+  void save_sag_solution(const string& fname) {
     FILE *f = fopen(fname.c_str(), "wt");
-    for(int i=0; i<N; i++)
-      fprintf(f, "%s;%d\n", vdata[i].name.c_str(), snakeid[i]);
+    for(int i=0; i<isize(sagid); i++)
+      fprintf(f, "%s;%d\n", vdata[i].name.c_str(), sagid[i]);
     fclose(f);
     }
   
@@ -370,19 +304,16 @@ namespace sag {
     int indist[30], pedge[30];
     for(int d=0; d<30; d++) indist[d] = 0, pedge[d] = 0;
     
+    int N = isize(sagid);
     for(int i=0; i<N; i++)
     for(int j=0; j<i; j++)
-      indist[snakedist(snakeid[i], snakeid[j])]++;
+      indist[sagdist[sagid[i]][sagid[j]]]++;
       
     for(int i=0; i<isize(sagedges); i++) {
       edgeinfo& ei = sagedges[i];
-      if(snakedist(snakeid[ei.i], snakeid[ei.j]) == 0) {
-        printf("zero between %d (%s) and %d (%s)\n", 
-          snakeid[ei.i], vdata[ei.i].name.c_str(),
-          snakeid[ei.j], vdata[ei.j].name.c_str());
-        }
+      if(ei.i != ei.j)
       if(ei.weight >= sag_edge->visible_from)
-        pedge[snakedist(snakeid[ei.i], snakeid[ei.j])]++;
+        pedge[sagdist[sagid[ei.i]][sagid[ei.j]]]++;
       }
     
     for(int d=0; d<30; d++) 
@@ -434,8 +365,10 @@ namespace sag {
     maxweight = 0;
     sag_edge = add_edgetype("SAG edge");
     fhstream f(fname, "rt");
-    if(!f.f) { printf("Failed to open SAG file: %s\n", fname); exit(1); }
-    // while(fgetc(f) != 10 && fgetc(f) != 13 && !feof(f)) ;
+    if(!f.f) {
+      printf("Failed to open SAG file: %s\n", fname);
+      throw "failed to open SAG file";
+      }
     while(!feof(f.f)) {
       string l1, l2;
       while(true) {
@@ -485,53 +418,39 @@ namespace sag {
     if(hub_filename != "")
       read_hubs(hub_filename);
     
-    N = isize(vdata);
-    // totwei.resize(N);
-    // for(int i=0; i<N; i++) totwei[i] = 0;
+    int DN = isize(vdata);
     
-    for(int i=0; i<N; i++) vdata[i].data = 0;
-    /* for(int i=0; i<isize(sagedges); i++) {
-      edgeinfo& ei = sagedges[i];
-      // maxwei[ei.i] = max(maxwei[ei.i], ei.weight);
-      // maxwei[ei.j] = max(maxwei[ei.j], ei.weight);
-      // totwei[ei.i] += ei.weight;
-      // totwei[ei.j] += ei.weight;
-      } */
+    for(int i=0; i<DN; i++) vdata[i].data = 0;
     for(int i=0; i<isize(sagedges); i++) {
       edgeinfo& ei = sagedges[i];
-      // (ei.weight >= maxwei[ei.i] / 5 || ei.weight >= maxwei[ei.j] / 5);
 
       ei.weight2 = pow((double) ei.weight, (double) edgepower) * edgemul;
-      // LANG:: pow(ei.weight, .4) / 50;      
       
-      // ei.weight2 = 0; int w = ei.weight; while(w) { w >>= 1; ei.weight2++; }      
-      /* if(totwei[ei.i] <= 0 || totwei[ei.j] <= 0) {
-        printf("BAD TOTWEI\n");
-        exit(1);
-        }
-      ei.weight2 = 3 * (
-        sqrt(ei.weight * 1. / totwei[ei.i]) * log(totwei[ei.i]) * log(totwei[ei.i]) +
-        sqrt(ei.weight * 1. / totwei[ei.j]) * log(totwei[ei.j]) * log(totwei[ei.j])); */
-      // printf("%f\n", ei.weight2);
       addedge0(ei.i, ei.j, &ei);
       }
   
-    initSnake(N*2);
-    printf("numsnake = %d\n", numsnake);
-    if(numsnake < N) {
-      printf("Error: snake does not fit\n");
+    if(legacy)
+      init_snake(2 * DN);
+    else
+      init_sag_cells();
+
+    compute_dists();
+
+    int SN = isize(sagcells);
+    if(SN < DN) {
+      println(hlog, "SN = ", SN, " DN = ", DN);
+      throw hr_exception("not enough cells for SAG");
       exit(1);
       }
-    snakeid.resize(N);
-    for(int i=0; i<N; i++) snakeid[i] = -1;
-    organize();
-    disable_snake();
+    sagid.resize(DN);
+    for(int i=0; i<DN; i++) sagid[i] = i;
+    create_sagnode();
 
-    for(int i=0; i<N; i++) {
+    for(int i=0; i<DN; i++) {
       int ii = i;
       vertexdata& vd = vdata[ii];
       vd.cp = colorpair(dftcolor);
-      createViz(ii, sag::snakecells[sag::snakeid[i]], Id);
+      createViz(ii, sagcells[sagid[i]], Id);
       }
 
     storeall();
@@ -556,7 +475,7 @@ int readArgs() {
     }
 
 // (1) configure edge weights
-  else if(argis("-edgepower")) {
+  else if(argis("-sag-edgepower")) {
     shift_arg_formula(sag::edgepower);
     shift_arg_formula(sag::edgemul);
     }
@@ -582,27 +501,48 @@ int readArgs() {
     shift(); hub_filename = args();
     }
 // (3) load the initial positioning
-  else if(argis("-gload")) {
-    PHASE(3); shift(); sag::loadsnake(args());
+  else if(argis("-sagload")) {
+    PHASE(3); shift(); sag::load_sag_solution(args());
     }
 // (4) perform simulated annealing: -fullsa <time in seconds>
-  else if(argis("-fullsa")) {
+  else if(argis("-sagfull")) {
     shift(); sag::dofullsa(argi());
     }
+  else if(argis("-sagviz")) {
+    sag::vizsa_start = SDL_GetTicks();
+    shift(); sag::vizsa_len = argi();
+    }
 // (5) save the positioning
-  else if(argis("-gsave")) {
-    PHASE(3); shift(); sag::savesnake(args());
+  else if(argis("-sagsave")) {
+    PHASE(3); shift(); sag::save_sag_solution(args());
     }
 // (6) output loglikelihood
-  else if(argis("-lik")) {
+  else if(argis("-sagloglik")) {
     sag::loglik();
     }
+  else if(argis("-sagmode")) {
+    shift();
+    sagmode = (eSagmode) argi();
+    if(sagmode == sagSA) {
+      shift(); temperature = argf();
+      }
+    }
   else return 1;
 #endif
   return 0;
   }
 
 bool turn(int delta) {
+  if(vizsa_start) {
+    auto t = ticks;
+    double d = (t-vizsa_start) / (1000. * vizsa_len);
+    if(d > 1) sagmode = sagOff;
+    else {
+      temperature = hightemp - (d*(hightemp-lowtemp));
+      sagmode = sagSA;
+      }
+    }
+  iterate();
   return false;
   // shmup::pc[0]->rebase();
   }
@@ -634,9 +574,10 @@ int ah = addHook(hooks_args, 100, readArgs)
           drawthemap();
           gmatrix0 = gmatrix;
     
+          slide_backup(rogueviz::sag::legacy, true);
           rogueviz::sag::read(RVPATH "roguelikes/edges.csv");
           rogueviz::readcolor(RVPATH "roguelikes/color.csv");
-          rogueviz::sag::loadsnake(RVPATH "roguelikes/" + cname());
+          rogueviz::sag::load_sag_solution(RVPATH "roguelikes/" + cname());
           })    
         }
       );
@@ -654,9 +595,10 @@ int ah = addHook(hooks_args, 100, readArgs)
       drawthemap();
       gmatrix0 = gmatrix;
 
+      slide_backup(rogueviz::sag::legacy, true);
       rogueviz::sag::read(RVPATH "lang/edges.csv");
       rogueviz::readcolor(RVPATH "lang/color.csv");
-      rogueviz::sag::loadsnake(RVPATH "lang/" + cname());
+      rogueviz::sag::load_sag_solution(RVPATH "lang/" + cname());
       if(euclid) rogueviz::legend.clear();
       })
     });
@@ -675,9 +617,10 @@ int ah = addHook(hooks_args, 100, readArgs)
       drawthemap();
       gmatrix0 = gmatrix;
 
+      slide_backup(rogueviz::sag::legacy, true);
       rogueviz::sag::read(RVPATH "boardgames/edges.csv");
       rogueviz::readcolor(RVPATH "boardgames/color.csv");
-      rogueviz::sag::loadsnake(RVPATH "boardgames/" + cname());
+      rogueviz::sag::load_sag_solution(RVPATH "boardgames/" + cname());
       })
         });