diff --git a/lib/index.js b/lib/index.js
index 741ae43..e912e09 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -7,17 +7,18 @@
 'use strict';
 
 var merge = require('merge'),
-	Row = require('./row'),
-	layoutConfig = {},
-	layoutData = {};
+	Row = require('./row');
 
 /**
-* Create a new, empty row.
-*
-* @method createNewRow
-* @return A new, empty row of the type specified by this layout.
-*/
-function createNewRow() {
+ * Create a new, empty row.
+ *
+ * @method createNewRow
+ * @param layoutConfig {Object} The layout configuration
+ * @param layoutData {Object} The current state of the layout
+ * @return A new, empty row of the type specified by this layout.
+ */
+
+function createNewRow(layoutConfig, layoutData) {
 
 	var isBreakoutRow;
 
@@ -48,10 +49,13 @@ function createNewRow() {
  * Note: the row must have already been completed.
  *
  * @method addRow
+ * @param layoutConfig {Object} The layout configuration
+ * @param layoutData {Object} The current state of the layout
  * @param row {Row} The row to add.
  * @return {Array} Each item added to the row.
  */
-function addRow(row) {
+
+function addRow(layoutConfig, layoutData, row) {
 
 	layoutData._rows.push(row);
 	layoutData._layoutItems = layoutData._layoutItems.concat(row.getItems());
@@ -63,14 +67,17 @@ function addRow(row) {
 }
 
 /**
-* Calculate the current layout for all items in the list that require layout.
-* "Layout" means geometry: position within container and size
-*
-* @method computeLayout
-* @param itemLayoutData {Array} Array of items to lay out, with data required to lay out each item
-* @return {Object} The newly-calculated layout, containing the new container height, and lists of layout items
-*/
-function computeLayout(itemLayoutData) {
+ * Calculate the current layout for all items in the list that require layout.
+ * "Layout" means geometry: position within container and size
+ *
+ * @method computeLayout
+ * @param layoutConfig {Object} The layout configuration
+ * @param layoutData {Object} The current state of the layout
+ * @param itemLayoutData {Array} Array of items to lay out, with data required to lay out each item
+ * @return {Object} The newly-calculated layout, containing the new container height, and lists of layout items
+ */
+
+function computeLayout(layoutConfig, layoutData, itemLayoutData) {
 
 	var laidOutItems = [],
 		itemAdded,
@@ -94,7 +101,7 @@ function computeLayout(itemLayoutData) {
 
 		// If not currently building up a row, make a new one.
 		if (!currentRow) {
-			currentRow = createNewRow();
+			currentRow = createNewRow(layoutConfig, layoutData);
 		}
 
 		// Attempt to add item to the current row.
@@ -103,14 +110,14 @@ function computeLayout(itemLayoutData) {
 		if (currentRow.isLayoutComplete()) {
 
 			// Row is filled; add it and start a new one
-			laidOutItems = laidOutItems.concat(addRow(currentRow));
+			laidOutItems = laidOutItems.concat(addRow(layoutConfig, layoutData, currentRow));
 
 			if (layoutData._rows.length >= layoutConfig.maxNumRows) {
 				currentRow = null;
 				return true;
 			}
 
-			currentRow = createNewRow();
+			currentRow = createNewRow(layoutConfig, layoutData);
 
 			// Item was rejected; add it to its own row
 			if (!itemAdded) {
@@ -120,12 +127,12 @@ function computeLayout(itemLayoutData) {
 				if (currentRow.isLayoutComplete()) {
 
 					// If the rejected item fills a row on its own, add the row and start another new one
-					laidOutItems = laidOutItems.concat(addRow(currentRow));
+					laidOutItems = laidOutItems.concat(addRow(layoutConfig, layoutData, currentRow));
 					if (layoutData._rows.length >= layoutConfig.maxNumRows) {
 						currentRow = null;
 						return true;
 					}
-					currentRow = createNewRow();
+					currentRow = createNewRow(layoutConfig, layoutData);
 				}
 			}
 		}
@@ -155,7 +162,7 @@ function computeLayout(itemLayoutData) {
 
 		}
 
-		laidOutItems = laidOutItems.concat(addRow(currentRow));
+		laidOutItems = laidOutItems.concat(addRow(layoutConfig, layoutData, currentRow));
 		layoutConfig._widowCount = currentRow.getItems().length;
 
 	}
@@ -175,14 +182,17 @@ function computeLayout(itemLayoutData) {
 }
 
 /**
-* Takes in a bunch of box data and config. Returns
-* geometry to lay them out in a justified view.
-*
-* @method covertSizesToAspectRatios
-* @param sizes {Array} Array of objects with widths and heights
-* @return {Array} A list of aspect ratios
-**/
+ * Takes in a bunch of box data and config. Returns
+ * geometry to lay them out in a justified view.
+ *
+ * @method covertSizesToAspectRatios
+ * @param sizes {Array} Array of objects with widths and heights
+ * @return {Array} A list of aspect ratios
+ */
+
 module.exports = function (input, config) {
+	var layoutConfig = {};
+	var layoutData = {};
 
 	// Defaults
 	var defaults = {
@@ -229,7 +239,7 @@ module.exports = function (input, config) {
 	layoutConfig._widowCount = 0;
 
 	// Convert widths and heights to aspect ratios if we need to
-	return computeLayout(input.map(function (item) {
+	return computeLayout(layoutConfig, layoutData, input.map(function (item) {
 		if (item.width && item.height) {
 			return { aspectRatio: item.width / item.height };
 		} else {
diff --git a/lib/row.js b/lib/row.js
index ade7002..fdff562 100644
--- a/lib/row.js
+++ b/lib/row.js
@@ -7,24 +7,25 @@
 var merge = require('merge');
 
 /**
-* Row
-* Wrapper for each row in a justified layout.
-* Stores relevant values and provides methods for calculating layout of individual rows.
-*
-* @param {Object} layoutConfig - The same as that passed
-* @param {Object} Initialization parameters. The following are all required:
-* @param params.top {Number} Top of row, relative to container
-* @param params.left {Number} Left side of row relative to container (equal to container left padding)
-* @param params.width {Number} Width of row, not including container padding
-* @param params.spacing {Number} Horizontal spacing between items
-* @param params.targetRowHeight {Number} Layout algorithm will aim for this row height
-* @param params.targetRowHeightTolerance {Number} Row heights may vary +/- (`targetRowHeight` x `targetRowHeightTolerance`)
-* @param params.edgeCaseMinRowHeight {Number} Absolute minimum row height for edge cases that cannot be resolved within tolerance.
-* @param params.edgeCaseMaxRowHeight {Number} Absolute maximum row height for edge cases that cannot be resolved within tolerance.
-* @param params.isBreakoutRow {Boolean} Is this row in particular one of those breakout rows? Always false if it's not that kind of photo list
-* @param params.widowLayoutStyle {String} If widows are visible, how should they be laid out?
-* @constructor
-*/
+ * Row
+ * Wrapper for each row in a justified layout.
+ * Stores relevant values and provides methods for calculating layout of individual rows.
+ *
+ * @param {Object} layoutConfig - The same as that passed
+ * @param {Object} Initialization parameters. The following are all required:
+ * @param params.top {Number} Top of row, relative to container
+ * @param params.left {Number} Left side of row relative to container (equal to container left padding)
+ * @param params.width {Number} Width of row, not including container padding
+ * @param params.spacing {Number} Horizontal spacing between items
+ * @param params.targetRowHeight {Number} Layout algorithm will aim for this row height
+ * @param params.targetRowHeightTolerance {Number} Row heights may vary +/- (`targetRowHeight` x `targetRowHeightTolerance`)
+ * @param params.edgeCaseMinRowHeight {Number} Absolute minimum row height for edge cases that cannot be resolved within tolerance.
+ * @param params.edgeCaseMaxRowHeight {Number} Absolute maximum row height for edge cases that cannot be resolved within tolerance.
+ * @param params.isBreakoutRow {Boolean} Is this row in particular one of those breakout rows? Always false if it's not that kind of photo list
+ * @param params.widowLayoutStyle {String} If widows are visible, how should they be laid out?
+ * @constructor
+ */
+
 var Row = module.exports = function (params) {
 
 	// Top of row, relative to container
@@ -66,25 +67,26 @@ var Row = module.exports = function (params) {
 Row.prototype = {
 
 	/**
-	* Attempt to add a single item to the row.
-	* This is the heart of the justified algorithm.
-	* This method is direction-agnostic; it deals only with sizes, not positions.
-	*
-	* If the item fits in the row, without pushing row height beyond min/max tolerance,
-	* the item is added and the method returns true.
-	*
-	* If the item leaves row height too high, there may be room to scale it down and add another item.
-	* In this case, the item is added and the method returns true, but the row is incomplete.
-	*
-	* If the item leaves row height too short, there are too many items to fit within tolerance.
-	* The method will either accept or reject the new item, favoring the resulting row height closest to within tolerance.
-	* If the item is rejected, left/right padding will be required to fit the row height within tolerance;
-	* if the item is accepted, top/bottom cropping will be required to fit the row height within tolerance.
-	*
-	* @method addItem
-	* @param itemData {Object} Item layout data, containing item aspect ratio.
-	* @return {Boolean} True if successfully added; false if rejected.
-	*/
+	 * Attempt to add a single item to the row.
+	 * This is the heart of the justified algorithm.
+	 * This method is direction-agnostic; it deals only with sizes, not positions.
+	 *
+	 * If the item fits in the row, without pushing row height beyond min/max tolerance,
+	 * the item is added and the method returns true.
+	 *
+	 * If the item leaves row height too high, there may be room to scale it down and add another item.
+	 * In this case, the item is added and the method returns true, but the row is incomplete.
+	 *
+	 * If the item leaves row height too short, there are too many items to fit within tolerance.
+	 * The method will either accept or reject the new item, favoring the resulting row height closest to within tolerance.
+	 * If the item is rejected, left/right padding will be required to fit the row height within tolerance;
+	 * if the item is accepted, top/bottom cropping will be required to fit the row height within tolerance.
+	 *
+	 * @method addItem
+	 * @param itemData {Object} Item layout data, containing item aspect ratio.
+	 * @return {Boolean} True if successfully added; false if rejected.
+	 */
+
 	addItem: function (itemData) {
 
 		var newItems = this.items.concat(itemData),
@@ -172,24 +174,25 @@ Row.prototype = {
 	},
 
 	/**
-	* Check if a row has completed its layout.
-	*
-	* @method isLayoutComplete
-	* @return {Boolean} True if complete; false if not.
-	*/
+	 * Check if a row has completed its layout.
+	 *
+	 * @method isLayoutComplete
+	 * @return {Boolean} True if complete; false if not.
+	 */
+
 	isLayoutComplete: function () {
 		return this.height > 0;
 	},
 
-
 	/**
-	* Set row height and compute item geometry from that height.
-	* Will justify items within the row unless instructed not to.
-	*
-	* @method completeLayout
-	* @param newHeight {Number} Set row height to this value.
-	* @param widowLayoutStyle {String} How should widows display? Supported: left | justify | center
-	*/
+	 * Set row height and compute item geometry from that height.
+	 * Will justify items within the row unless instructed not to.
+	 *
+	 * @method completeLayout
+	 * @param newHeight {Number} Set row height to this value.
+	 * @param widowLayoutStyle {String} How should widows display? Supported: left | justify | center
+	 */
+
 	completeLayout: function (newHeight, widowLayoutStyle) {
 
 		var itemWidthSum = this.left,
@@ -289,13 +292,14 @@ Row.prototype = {
 	},
 
 	/**
-	* Force completion of row layout with current items.
-	*
-	* @method forceComplete
-	* @param fitToWidth {Boolean} Stretch current items to fill the row width.
-	*                             This will likely result in padding.
-	* @param fitToWidth {Number}
-	*/
+	 * Force completion of row layout with current items.
+	 *
+	 * @method forceComplete
+	 * @param fitToWidth {Boolean} Stretch current items to fill the row width.
+	 *                             This will likely result in padding.
+	 * @param fitToWidth {Number}
+	 */
+
 	forceComplete: function (fitToWidth, rowHeight) {
 
 		// TODO Handle fitting to width
@@ -317,12 +321,13 @@ Row.prototype = {
 	},
 
 	/**
-	* Return layout data for items within row.
-	* Note: returns actual list, not a copy.
-	*
-	* @method getItems
-	* @return Layout data for items within row.
-	*/
+	 * Return layout data for items within row.
+	 * Note: returns actual list, not a copy.
+	 *
+	 * @method getItems
+	 * @return Layout data for items within row.
+	 */
+
 	getItems: function () {
 		return this.items;
 	}