diff --git a/src/main/java/precomp/Mask.java b/src/main/java/precomp/Mask.java
index 4ffcd23..6e5986b 100644
--- a/src/main/java/precomp/Mask.java
+++ b/src/main/java/precomp/Mask.java
@@ -17,5 +17,12 @@ public sealed interface Mask
    int place();
    byte d();
    default byte letter()    { return (byte) (d() | 64); }
-   default byte clueChar()  { return (byte) (d() | 48); }
+   default void letter(byte[] template, int minR, int minC, int height, int width) {
+      int rr = r() - minR;
+      int cc = c() - minC;
+      if (rr >= 0 && rr < height && cc >= 0 && cc < width) {
+         template[rr * (width + 1) + cc] = letter();
+      }
+   }
+   default byte clueChar() { return (byte) (d() | 48); }
 }
\ No newline at end of file
diff --git a/src/main/java/puzzle/Export.java b/src/main/java/puzzle/Export.java
index 153cddc..86b46fe 100644
--- a/src/main/java/puzzle/Export.java
+++ b/src/main/java/puzzle/Export.java
@@ -33,8 +33,6 @@ public record Export() {
    @Shaped static final byte   SPACE                     = Const9x8.SPACE;
    @Shaped static final byte   LINE_BREAK                = Const9x8.LINE_BREAK;
    @Shaped static final byte   DASH                      = Const9x8.DASH;
-   @Shaped static final int    R                         = Const9x8.R;
-   @Shaped static final int    C                         = Const9x8.C;
    @Shaped static final int    SIZE                      = Const9x8.SIZE;
    @Shaped static final byte[] INIT_GRID_OUTPUT_ARR      = Const9x8.INIT_GRID_OUTPUT_ARR;
    @Shaped static final byte[] INIT_GRID_OUTPUT_DASH_ARR = Const9x8.INIT_GRID_OUTPUT_DASH_ARR;
@@ -44,19 +42,14 @@ public record Export() {
    
    public static final ThreadLocal<ExportTemplates> BYTES = ThreadLocal.withInitial(
            () -> new ExportTemplates(INIT_GRID_OUTPUT_ARR, INIT_GRID_OUTPUT_DASH_ARR, new byte[8]));
-   static int HI(int in)               { return in | 64; }
-   static byte LETTER(int in)          { return (byte) (in | 64); }
-   static byte CLUE_CHAR(int s)        { return (byte) (s | 48); }
-   static int INDEX_ROW(int idx)       { return idx % R; }
-   static int INDEX_COL(int idx)       { return idx / R; }
-   static int INDEX(int idx, int cols) { return INDEX_ROW(idx) * cols + INDEX_COL(idx); }
+   static int HI(int in) { return in | 64; }
    
    public static String gridToString(Clues clues) {
       val chars = BYTES.get().table();
-      var signa = new Signa(clues);
-      signa.forEach(v -> chars[INDEX(v.index(), C + 1)] = CLUE_CHAR(v.clue()));
+      var signa = new Signa(clues).map(v -> CELLS[v.cellIndex()]).toArray(Mask[]::new);
+      Arrays.stream(signa).forEach(v -> chars[v.place()] = v.clueChar());
       val result = new String(chars);
-      signa.forEach(v -> chars[INDEX(v.index(), C + 1)] = SPACE);
+      Arrays.stream(signa).forEach(v -> chars[v.place()] = SPACE);
       return result;
    }
    
@@ -66,7 +59,7 @@ public record Export() {
       public Puzzle {
          for (var l = grid.lo & MASK_LO & ~cl.lo; l != X; l &= l - 1) set(Long.numberOfTrailingZeros(l), cells, grid.g);
          for (var h = grid.hi & MASK_HI & ~cl.hi; h != X; h &= h - 1) set(HI(Long.numberOfTrailingZeros(h)), cells, grid.g);
-         new Signa(cl).forEach(v -> cells[v.index()] = CELLS[v.index() * 33 + 27 + Slot.dir(v.clue())]);
+         new Signa(cl).forEach(v -> cells[v.index()] = CELLS[v.cellIndex()]);
       }
       static void set(int idx, Mask[] cells, byte[] read) { cells[idx] = CELLS[idx * 33 + read[idx]]; }
       public Puzzle(Grid grid, Clues cl)                  { this(grid, new Mask[grid.g.length], cl); }
@@ -81,7 +74,7 @@ public record Export() {
       public Puzzle sync() {
          for (var l = grid.lo & MASK_LO & ~cl.lo; l != X; l &= l - 1) set(Long.numberOfTrailingZeros(l), cells, grid.g);
          for (var h = grid.hi & MASK_HI & ~cl.hi; h != X; h &= h - 1) set(HI(Long.numberOfTrailingZeros(h)), cells, grid.g);
-         new Signa(cl).forEach(v -> cells[v.index()] = CELLS[v.index() * 33 + 27 + Slot.dir(v.clue())]);
+         new Signa(cl).forEach(v -> cells[v.index()] = CELLS[v.cellIndex()]);
          return this;
       }
    }
@@ -128,13 +121,7 @@ public record Export() {
          Arrays.fill(template, DASH);
          for (int i = width; i < template.length; i += width + 1) template[i] = LINE_BREAK;
          
-         puzzle.forEach(l -> {
-            int rr = l.r() - MINR;
-            int cc = l.c() - MINC;
-            if (rr >= 0 && rr < height && cc >= 0 && cc < width) {
-               template[rr * (width + 1) + cc] = l.letter();
-            }
-         });
+         puzzle.forEach(l -> l.letter(template, MINR, MINC, height, width));
          var grid = new String(template).split("\n");
          // 5) words output with cropped coordinates
          
diff --git a/src/main/java/puzzle/Riddle.java b/src/main/java/puzzle/Riddle.java
index 1c719bc..866c50f 100644
--- a/src/main/java/puzzle/Riddle.java
+++ b/src/main/java/puzzle/Riddle.java
@@ -86,7 +86,12 @@ public class Riddle {
       public static Clue from(int dir) { return CLUES[dir]; }
    }
    
-   public record Vestigium(int index, int clue) { }
+   public record Vestigium(int index, int clue) {
+      
+      public int cellIndex() {
+         return index * 33 + 27 + Slot.dir(clue);
+      }
+   }
    
    public record ExportedPuzzle(String[] grid, WordOut[] words, int difficulty, Rewards rewards) { }