diff --git a/src/field.js b/src/field.js
index 053b72c..279c6d7 100644
--- a/src/field.js
+++ b/src/field.js
@@ -179,18 +179,20 @@ class Field extends component.Component {
     throw new Error(`field.fill needs array or number, got ${v}`);
   }
 
-  pack() {
+  toArrays() {
     let newPitch = this.width;
     let numPixels = this.height * newPitch;
-    let newBuff = new Uint8Array(numPixels);
+    let newArrays = new Array(this.height);
     for (let y = 0; y < this.height; y++) {
+      let newRow = new Array(this.width);
       for (let x = 0; x < this.width; x++) {
         let k = y*this.pitch + x;
         let j = y*newPitch + x;
-        newBuff[j] = this.data[k];
+        newRow[x] = this.data[k];
       }
+      newArrays[y] = newRow;
     }
-    return newBuff;
+    return newArrays;
   }
 
   xform(kind) {
diff --git a/src/tileset_builder.js b/src/tileset_builder.js
index 4854b99..f071935 100644
--- a/src/tileset_builder.js
+++ b/src/tileset_builder.js
@@ -12,7 +12,7 @@ class TilesetBuilderDisplay extends baseDisplay.BaseDisplay {
     }
     this._tileset = new tiles.Tileset(details);
     this._frames = [];
-    this._numFrames = info.numFrames || 64;
+    this._numFrames = info.numFrames || 256;
   }
 
   name() {
diff --git a/test/cycle_palette.js b/test/cycle_palette.js
index 0ac4a20..e3f5550 100644
--- a/test/cycle_palette.js
+++ b/test/cycle_palette.js
@@ -27,17 +27,17 @@ describe('Cycle palette', function() {
 
     util.renderCompareTo(ra, 'test/testdata/green-fruit.png');
 
-    let expect = new Uint8Array([
-      0, 0, 0, 0, 4, 0, 0, 0,
-      0, 0, 0, 0, 0, 4, 0, 0,
-      0, 2, 8, 8, 8, 4, 2, 0,
-      2, 8,14, 8, 4, 8, 8, 2,
-      8,14,14, 8, 8, 8, 8, 8,
-      8, 8, 8, 8, 8, 8, 8, 8,
-      0, 8, 8, 8, 8, 8, 8, 0,
-      0, 0, 8, 8, 8, 8, 0, 0
-    ]);
-    assert.deepEqual(expect, ra.field.pack());
+    let expect = [
+     [ 0, 0, 0, 0, 4, 0, 0, 0],
+     [ 0, 0, 0, 0, 0, 4, 0, 0],
+     [ 0, 2, 8, 8, 8, 4, 2, 0],
+     [ 2, 8,14, 8, 4, 8, 8, 2],
+     [ 8,14,14, 8, 8, 8, 8, 8],
+     [ 8, 8, 8, 8, 8, 8, 8, 8],
+     [ 0, 8, 8, 8, 8, 8, 8, 0],
+     [ 0, 0, 8, 8, 8, 8, 0, 0],
+    ];
+    assert.deepEqual(expect, ra.field.toArrays());
 
     // Compare the palette
     palette = ra.palette;
@@ -171,17 +171,17 @@ describe('Cycle palette', function() {
     let img = ra.loadImage('test/testdata/small-fruit.png');
     ra.paste(img);
 
-    let expect = new Uint8Array([
-      1, 1, 1, 1, 4, 1, 1, 1,
-      1, 1, 1, 1, 1, 4, 1, 1,
-      1, 2, 0, 0, 0, 4, 2, 1,
-      2, 0, 3, 0, 4, 0, 0, 2,
-      0, 3, 3, 0, 0, 0, 0, 0,
-      0, 0, 0, 0, 0, 0, 0, 0,
-      1, 0, 0, 0, 0, 0, 0, 1,
-      1, 1, 0, 0, 0, 0, 1, 1
-    ]);
-    assert.deepEqual(expect, ra.field.pack());
+    let expect = [
+      [1, 1, 1, 1, 4, 1, 1, 1],
+      [1, 1, 1, 1, 1, 4, 1, 1],
+      [1, 2, 0, 0, 0, 4, 2, 1],
+      [2, 0, 3, 0, 4, 0, 0, 2],
+      [0, 3, 3, 0, 0, 0, 0, 0],
+      [0, 0, 0, 0, 0, 0, 0, 0],
+      [1, 0, 0, 0, 0, 0, 0, 1],
+      [1, 1, 0, 0, 0, 0, 1, 1],
+    ];
+    assert.deepEqual(expect, ra.field.toArrays());
 
     // Compare the palette
     let palette = ra.palette;
diff --git a/test/plane.js b/test/field.js
similarity index 84%
rename from test/plane.js
rename to test/field.js
index 5a40991..b133838 100644
--- a/test/plane.js
+++ b/test/field.js
@@ -11,14 +11,14 @@ describe('Field', function() {
                     [0,0,0,7],
                     [0,7,7,0],
                    ]);
-    let bin = pl.pack();
+    let bin = pl.toArrays();
 
-    let expect = new Uint8Array([
-      0, 7, 7, 0,
-      7, 7, 0, 7,
-      0, 0, 0, 7,
-      0, 7, 7, 0,
-    ]);
+    let expect = [
+      [0, 7, 7, 0],
+      [7, 7, 0, 7],
+      [0, 0, 0, 7],
+      [0, 7, 7, 0],
+    ];
     assert.deepEqual(expect, bin);
   });
 
@@ -38,14 +38,14 @@ describe('Field', function() {
     let pl = new ra.Field();
     pl.setSize(4, 4);
     pl.fill(5);
-    let bin = pl.pack();
+    let bin = pl.toArrays();
 
-    let expect = new Uint8Array([
-      5, 5, 5, 5,
-      5, 5, 5, 5,
-      5, 5, 5, 5,
-      5, 5, 5, 5,
-    ]);
+    let expect = [
+      [5, 5, 5, 5],
+      [5, 5, 5, 5],
+      [5, 5, 5, 5],
+      [5, 5, 5, 5],
+    ];
     assert.deepEqual(expect, bin);
   });
 
@@ -56,14 +56,14 @@ describe('Field', function() {
              7,7,0,7,
              0,0,0,7,
              0,7,7,0]);
-    let bin = pl.pack();
+    let bin = pl.toArrays();
 
-    let expect = new Uint8Array([
-      0, 7, 7, 0,
-      7, 7, 0, 7,
-      0, 0, 0, 7,
-      0, 7, 7, 0,
-    ]);
+    let expect = [
+      [0, 7, 7, 0],
+      [7, 7, 0, 7],
+      [0, 0, 0, 7],
+      [0, 7, 7, 0],
+    ];
     assert.deepEqual(expect, bin);
   });
 
diff --git a/test/hsv_sort.js b/test/hsv_sort.js
index c041880..ee91beb 100644
--- a/test/hsv_sort.js
+++ b/test/hsv_sort.js
@@ -22,14 +22,14 @@ describe('HSV sort', function() {
       util.ensureFilesMatch('test/testdata/pal_sphere.png', tmpout);
 
       // Compare the field data buffer
-      let bin = ra.field.pack();
+      let bin = ra.field.toArrays();
       let pitch = 16;
 
       let actual = '';
       for (let y = 0; y < 16; y++) {
         for (let x = 0; x < 16; x++) {
           let k = y*pitch+x;
-          actual += `${bin[k]} `;
+          actual += `${bin[y][x]} `;
         }
         actual += '\n';
       }
@@ -76,7 +76,7 @@ describe('HSV sort', function() {
       ra.save(pal, tmpout);
       util.ensureFilesMatch('test/testdata/pal_sphere_sort.png', tmpout);
 
-      let bin = ra.field.pack();
+      let bin = ra.field.toArrays();
       let pitch = 16;
 
       // Compare the field data buffer
@@ -84,7 +84,7 @@ describe('HSV sort', function() {
       for (let y = 0; y < 16; y++) {
         for (let x = 0; x < 16; x++) {
           let k = y*pitch+x;
-          actual += `${bin[k]} `;
+          actual += `${bin[y][x]} `;
         }
         actual += '\n';
       }
diff --git a/test/image.js b/test/image.js
index 89c90a2..29f24ed 100644
--- a/test/image.js
+++ b/test/image.js
@@ -47,17 +47,17 @@ describe('Image', function() {
     util.renderCompareTo(ra, 'test/testdata/small-fruit.png');
 
     // 8-bit data array is using pico8 values
-    let expect = new Uint8Array([
-      0, 0, 0, 0, 4, 0, 0, 0,
-      0, 0, 0, 0, 0, 4, 0, 0,
-      0, 2, 8, 8, 8, 4, 2, 0,
-      2, 8,14, 8, 4, 8, 8, 2,
-      8,14,14, 8, 8, 8, 8, 8,
-      8, 8, 8, 8, 8, 8, 8, 8,
-      0, 8, 8, 8, 8, 8, 8, 0,
-      0, 0, 8, 8, 8, 8, 0, 0
-    ]);
-    assert.deepEqual(expect, ra.field.pack());
+    let expect = [
+      [0, 0, 0, 0, 4, 0, 0, 0],
+      [0, 0, 0, 0, 0, 4, 0, 0],
+      [0, 2, 8, 8, 8, 4, 2, 0],
+      [2, 8,14, 8, 4, 8, 8, 2],
+      [8,14,14, 8, 8, 8, 8, 8],
+      [8, 8, 8, 8, 8, 8, 8, 8],
+      [0, 8, 8, 8, 8, 8, 8, 0],
+      [0, 0, 8, 8, 8, 8, 0, 0],
+    ];
+    assert.deepEqual(expect, ra.field.toArrays());
   });
 
 
@@ -71,17 +71,17 @@ describe('Image', function() {
 
     util.renderCompareTo(ra, 'test/testdata/small-fruit.png');
 
-    let expect = new Uint8Array([
-      0, 0, 0, 0, 1, 0, 0, 0,
-      0, 0, 0, 0, 0, 1, 0, 0,
-      0, 4, 2, 2, 2, 1, 4, 0,
-      4, 2, 5, 2, 1, 2, 2, 4,
-      2, 5, 5, 2, 2, 2, 2, 2,
-      2, 2, 2, 2, 2, 2, 2, 2,
-      0, 2, 2, 2, 2, 2, 2, 0,
-      0, 0, 2, 2, 2, 2, 0, 0
-    ]);
-    assert.deepEqual(expect, ra.field.pack());
+    let expect = [
+      [0, 0, 0, 0, 1, 0, 0, 0],
+      [0, 0, 0, 0, 0, 1, 0, 0],
+      [0, 4, 2, 2, 2, 1, 4, 0],
+      [4, 2, 5, 2, 1, 2, 2, 4],
+      [2, 5, 5, 2, 2, 2, 2, 2],
+      [2, 2, 2, 2, 2, 2, 2, 2],
+      [0, 2, 2, 2, 2, 2, 2, 0],
+      [0, 0, 2, 2, 2, 2, 0, 0],
+    ];
+    assert.deepEqual(expect, ra.field.toArrays());
 
     // Compare the palette
     let palette = ra.palette;
@@ -160,17 +160,17 @@ describe('Image', function() {
     util.renderCompareTo(ra, 'test/testdata/small-fruit-quant.png');
 
     // 8-bit data array is using pico8 values
-    let expect = new Uint8Array([
-       1, 1,39, 1, 3,32,27,38,
-       0,30,36,28,31, 5,40,26,
-      37,42, 9,14, 7, 4,45,35,
-      43,54,58,21,24,55,19,44,
-      17,57,59,50,15,18,46,22,
-      53, 6,56,48,47, 8,13,16,
-      41,51,20,10,17,18,52,34,
-      25,29,12,11,23,49,33, 2,
-    ]);
-    assert.deepEqual(expect, ra.field.pack());
+    let expect = [
+      [ 1, 1,39, 1, 3,32,27,38],
+      [ 0,30,36,28,31, 5,40,26],
+      [37,42, 9,14, 7, 4,45,35],
+      [43,54,58,21,24,55,19,44],
+      [17,57,59,50,15,18,46,22],
+      [53, 6,56,48,47, 8,13,16],
+      [41,51,20,10,17,18,52,34],
+      [25,29,12,11,23,49,33, 2],
+    ];
+    assert.deepEqual(expect, ra.field.toArrays());
   });
 
 
diff --git a/test/tileset.js b/test/tileset.js
index 108c5d4..8c97e66 100644
--- a/test/tileset.js
+++ b/test/tileset.js
@@ -356,13 +356,13 @@ describe('Tileset', function() {
     assert.equal(tiles.length, 8);
     assert.equal(tiles.numTiles, 8);
 
-    let pattern = ra.field.pack();
-    let expect = new Uint8Array([
-      0, 1, 2, 3,
-      1, 4, 4, 4,
-      5, 5, 2, 6,
-      1, 7, 0, 0,
-    ]);
+    let pattern = ra.field.toArrays();
+    let expect = [
+      [0, 1, 2, 3],
+      [1, 4, 4, 4],
+      [5, 5, 2, 6],
+      [1, 7, 0, 0],
+    ];
     assert.deepEqual(expect, pattern);
     assert.deepEqual(4, ra.field.width);
     assert.deepEqual(4, ra.field.height);