diff --git a/main.js b/main.js
index 0cd0e63..e6a9dac 100644
--- a/main.js
+++ b/main.js
@@ -11,14 +11,14 @@ const globals = {
 };
 
 const btnStart_onClick = () => {
-    globals.grid = makeGrid(4, 4, {value: 0, visible: false});
-    addRandomTile();
-    // globals.grid = makeDevGrid([ // can't slide down or left
-    //     [0,0,1,0],
-    //     [0,0,0,0],
-    //     [0,0,0,0],
-    //     [3,2,3,0],
-    // ]);
+    // globals.grid = makeGrid(4, 4, {value: 0, visible: false});
+    // addRandomTile();
+    globals.grid = makeDevGrid([ // can't slide down or left
+        [1,0,0,0],
+        [0,0,0,0],
+        [0,0,0,0],
+        [0,0,0,0],
+    ]);
     redraw(globals.grid);
 }
 
@@ -26,16 +26,137 @@ const btnRedraw_onClick = () => {
     redraw(globals.grid);
 }
 
+const doTheLoop = (advance, getVector, getFromIndex, getToIndex, testForDone, swap, merge, length) => {
+    let didIDoIt = false;
+    for (let index = 0; index < length; index++) {
+        const vector = getVector(index);
+        const swap2 = swap.bind(this, vector, index);
+        const fromIndex = getFromIndex(vector.length);
+        const toIndex = getToIndex(vector.length);
+        const didChangeThisPass = slide(fromIndex, toIndex, vector, advance, swap2, merge, testForDone);
+        didIDoIt = didIDoIt || didChangeThisPass;
+    }
+    return didIDoIt;
+}
+
+const slideVertical = (grid, direction) => {
+    const advanceForward = i => i - 1;
+    const advanceBackward = i => i + 1;
+    const testForDoneForward = fromIndex => fromIndex < 0;
+    const testForDoneBackward = (fromIndex, length) => fromIndex >= length;
+    const getFromIndexForward = (length) => length - 2;
+    const getFromIndexBackward = () => 1;
+    const getToIndexForward = (length) => length - 1;
+    const getToIndexBackward = () => 0;
+    const getColumn = (index) =>  grid.getColumn(index);
+    const getRow = (index) => grid.getRow(index);
+    const swapInRow = (vector, rowIndex, from, to) => {
+        grid.swapTiles(rowIndex, from, rowIndex, to);
+        const tempTile = vector[to];
+        vector[to] = vector[from];
+        vector[from] = tempTile;
+    };
+    const swapInColumn = (vector, columnIndex, from, to) => {
+        grid.swapTiles(from, columnIndex, to, columnIndex);
+        const tempTile = vector[to];
+        vector[to] = vector[from];
+        vector[from] = tempTile;        
+    }
+        const merge = (from, to) => {
+        to.value++;
+        from.value = 0;
+        from.visible = false;
+    };
+
+    switch(direction) {
+        case Direction.Up: {
+            const advance = advanceBackward;
+            const getVector = getColumn;
+            const getFromIndex = getFromIndexBackward;
+            const getToIndex = getToIndexBackward;
+            const testForDone = testForDoneBackward;
+            const swap = swapInColumn;
+            const length = grid.numColumns;
+            return doTheLoop(advance, getVector, getFromIndex, getToIndex, testForDone, swap, merge, length);
+        }
+        case Direction.Down: {
+            const advance = advanceForward;
+            const getVector = getColumn;
+            const getFromIndex = getFromIndexForward;
+            const getToIndex = getToIndexForward;
+            const testForDone = testForDoneForward;
+            const swap = swapInColumn;
+            const length = grid.numColumns;
+            return doTheLoop(advance, getVector, getFromIndex, getToIndex, testForDone, swap, merge, length);
+        }
+    }
+    return false;
+}
+
+const slideHorizontal = (grid, direction) => {
+    const advanceForward = i => i - 1;
+    const advanceBackward = i => i + 1;
+    const testForDoneForward = fromIndex => fromIndex < 0;
+    const testForDoneBackward = (fromIndex, length) => fromIndex >= length;
+    const getFromIndexForward = (length) => length - 2;
+    const getFromIndexBackward = () => 1;
+    const getToIndexForward = (length) => length - 1;
+    const getToIndexBackward = () => 0;
+    const getColumn = (index) =>  grid.getColumn(index);
+    const getRow = (index) => grid.getRow(index);
+    const swapInRow = (vector, rowIndex, from, to) => {
+        grid.swapTiles(rowIndex, from, rowIndex, to);
+        const tempTile = vector[to];
+        vector[to] = vector[from];
+        vector[from] = tempTile;
+    };
+    const swapInColumn = (vector, columnIndex, from, to) => {
+        grid.swapTiles(from, columnIndex, to, columnIndex);
+        const tempTile = vector[to];
+        vector[to] = vector[from];
+        vector[from] = tempTile;        
+    }
+    const merge = (from, to) => {
+        to.value++;
+        from.value = 0;
+        from.visible = false;
+    };
+
+    switch (direction) {
+        case Direction.Left: {
+            const advance = advanceBackward;
+            const getVector = getRow;
+            const getFromIndex = getFromIndexBackward;
+            const getToIndex = getToIndexBackward;
+            const testForDone = testForDoneBackward;
+            const swap = swapInRow;
+            const length = grid.numRows;
+            return doTheLoop(advance, getVector, getFromIndex, getToIndex, testForDone, swap, merge, length);
+        }
+        case Direction.Right: {
+            const advance = advanceForward;
+            const getVector = getRow;
+            const getFromIndex = getFromIndexForward;
+            const getToIndex = getToIndexForward;
+            const testForDone = testForDoneForward;
+            const swap = swapInRow;
+            const length = grid.numRows;
+            return doTheLoop(advance, getVector, getFromIndex, getToIndex, testForDone, swap, merge, length);
+        }
+    }
+    return false;
+}
+
 const slideInDirection = (grid, direction) => {
     switch(direction) {
         case Direction.Up:
-            return slideUp(grid);
+            return slideVertical(grid, direction);
         case Direction.Down:
-            return slideDown(grid);
+            return slideVertical(grid, direction);
         case Direction.Left:
-            return slideLeft(grid);
+            return slideHorizontal(grid, direction);
         case Direction.Right:
-            return slideRight(grid);
+            return slideHorizontal(grid, direction);
         default:
             return false;
     }
@@ -48,7 +169,7 @@ const playMove = (grid, direction) => {
     } else {
         alert(`Unable to slide ${direction.name}.`);
     }
-    checkForEnd(grid);
+    // checkForEnd(grid);
 }
 
 const btnUp_onClick = () => {
@@ -71,9 +192,10 @@ const drawGrid = (grid, element) => {
     // grid is our grid
     // element is our div
     let text = "<table cellspacing=\"0\">\n";
-    for (const row of grid.rows) {
+    for (let rowIndex = 0; rowIndex < grid.numRows; rowIndex++) {
         text += "  <tr>\n";
-        for (const tile of row) {
+        for (let columnIndex = 0; columnIndex < grid.numColumns; columnIndex++) {
+            const tile = grid.getTile(rowIndex, columnIndex);
             text += "    <td title=\"(" + tile.originalLocation.row + ", " + tile.originalLocation.column + ")\"class=\"" + (tile.visible ? "visible " : "hidden ") + "\">" + tile.value + "</td>\n";
         }
         text += "  </tr>\n";
@@ -133,13 +255,13 @@ const makeGrid = (numRows, numColumns, initialValue) => {
         },
         getTile: (row, column) => {
             if (row >= 0 && row < numRows && column >= 0 && column < numColumns) {
-                return rows[row][column];
+                return rows[column][row];
             }
             return null;
         },
         setTile: (row, column, tile) => {
             if (row >= 0 && row < numRows && column >= 0 && column < numColumns) {
-                rows[row][column] = tile;
+                rows[column][row] = tile;
             }
         },
         swapTiles: (fromRow, fromColumn, toRow, toColumn) => {
@@ -197,16 +319,9 @@ const redraw = (grid) => {
 }
 
 const slide = (fromIndex, toIndex, vector, advance, swap, merge, testForDone) => {
-    // const oldSwap = swap;
-    // swap = (fromIndex, toIndex) => {
-    //     const temp = vector[toIndex];
-    //     vector[toIndex] = vector[fromIndex];
-    //     vector[fromIndex] = temp;
-    //     oldSwap(fromIndex, toIndex);
-    // };
     let didIDoIt = false;
     let hasMergedPrevious = false;
-    while(!testForDone(fromIndex)) {
+    while(!testForDone(fromIndex, vector.length)) {
         const fromTile = vector[fromIndex];
         const toTile = toIndex < vector.length && toIndex >= 0 ? vector[toIndex] : null;
         if (toTile == null) {