diff --git a/src/pocketmine/Player.php b/src/pocketmine/Player.php
index d2dbd3c02..21cd48b7f 100644
--- a/src/pocketmine/Player.php
+++ b/src/pocketmine/Player.php
@@ -72,7 +72,6 @@ use pocketmine\form\FormValidationException;
 use pocketmine\inventory\CraftingGrid;
 use pocketmine\inventory\Inventory;
 use pocketmine\inventory\PlayerCursorInventory;
-use pocketmine\inventory\PlayerUIInventory;
 use pocketmine\inventory\transaction\action\InventoryAction;
 use pocketmine\inventory\transaction\CraftingTransaction;
 use pocketmine\inventory\transaction\InventoryTransaction;
@@ -290,8 +289,8 @@ class Player extends Human implements CommandSender, ChunkLoader, IPlayer{
 	protected $windowIndex = [];
 	/** @var bool[] */
 	protected $permanentWindows = [];
-	/** @var PlayerUIInventory */
-	protected $playerUIInventory;
+	/** @var PlayerCursorInventory */
+	protected $cursorInventory;
 	/** @var CraftingGrid */
 	protected $craftingGrid = null;
 	/** @var CraftingTransaction|null */
@@ -3554,7 +3553,7 @@ class Player extends Human implements CommandSender, ChunkLoader, IPlayer{
 			$this->removeAllWindows(true);
 			$this->windows = [];
 			$this->windowIndex = [];
-			$this->playerUIInventory = null;
+			$this->cursorInventory = null;
 			$this->craftingGrid = null;
 
 			if($this->constructed){
@@ -3819,19 +3818,15 @@ class Player extends Human implements CommandSender, ChunkLoader, IPlayer{
 
 		$this->addWindow($this->getArmorInventory(), ContainerIds::ARMOR, true);
 
-		$this->playerUIInventory = new PlayerUIInventory($this);
-		$this->addWindow($this->playerUIInventory, ContainerIds::UI, true);
+		$this->cursorInventory = new PlayerCursorInventory($this);
+		$this->addWindow($this->cursorInventory, ContainerIds::UI, true);
 
-		$this->craftingGrid = new CraftingGrid($this->playerUIInventory, CraftingGrid::SIZE_SMALL);
+		$this->craftingGrid = new CraftingGrid($this, CraftingGrid::SIZE_SMALL);
 		//TODO: more windows
 	}
 
-	public function getPlayerUIInventory() : PlayerUIInventory{
-		return $this->playerUIInventory;
-	}
-
 	public function getCursorInventory() : PlayerCursorInventory{
-		return $this->playerUIInventory->getCursorInventory();
+		return $this->cursorInventory;
 	}
 
 	public function getCraftingGrid() : CraftingGrid{
@@ -3847,7 +3842,7 @@ class Player extends Human implements CommandSender, ChunkLoader, IPlayer{
 
 	public function doCloseInventory() : void{
 		/** @var Inventory[] $inventories */
-		$inventories = [$this->craftingGrid, $this->getCursorInventory()];
+		$inventories = [$this->craftingGrid, $this->cursorInventory];
 		foreach($inventories as $inventory){
 			$contents = $inventory->getContents();
 			if(count($contents) > 0){
@@ -3861,7 +3856,7 @@ class Player extends Human implements CommandSender, ChunkLoader, IPlayer{
 		}
 
 		if($this->craftingGrid->getGridWidth() > CraftingGrid::SIZE_SMALL){
-			$this->craftingGrid = new CraftingGrid($this->playerUIInventory, CraftingGrid::SIZE_SMALL);
+			$this->craftingGrid = new CraftingGrid($this, CraftingGrid::SIZE_SMALL);
 		}
 	}
 
diff --git a/src/pocketmine/block/CraftingTable.php b/src/pocketmine/block/CraftingTable.php
index 9e416e872..05b52fd6a 100644
--- a/src/pocketmine/block/CraftingTable.php
+++ b/src/pocketmine/block/CraftingTable.php
@@ -49,7 +49,7 @@ class CraftingTable extends Solid{
 
 	public function onActivate(Item $item, Player $player = null) : bool{
 		if($player instanceof Player){
-			$player->setCraftingGrid(new CraftingGrid($player->getPlayerUIInventory(), CraftingGrid::SIZE_BIG));
+			$player->setCraftingGrid(new CraftingGrid($player, CraftingGrid::SIZE_BIG));
 		}
 
 		return true;
diff --git a/src/pocketmine/inventory/BaseUIInventory.php b/src/pocketmine/inventory/BaseUIInventory.php
deleted file mode 100644
index 3636e3ab7..000000000
--- a/src/pocketmine/inventory/BaseUIInventory.php
+++ /dev/null
@@ -1,116 +0,0 @@
-<?php
-
-/*
- *
- *  ____            _        _   __  __ _                  __  __ ____
- * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
- * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
- * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
- * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Lesser General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * @author PocketMine Team
- * @link http://www.pocketmine.net/
- *
- *
-*/
-
-declare(strict_types=1);
-
-namespace pocketmine\inventory;
-
-use pocketmine\item\Item;
-use pocketmine\item\ItemFactory;
-use pocketmine\Player;
-
-class BaseUIInventory extends BaseInventory{
-
-	protected $inventory;
-	protected $size;
-	protected $offset;
-
-	public function __construct(PlayerUIInventory $inventory, int $size, int $offset){
-		$this->inventory = $inventory;
-		$this->size = $size;
-		$this->offset = $offset;
-		parent::__construct([], $size);
-	}
-
-	public function getName() : string{
-		return "UI";
-	}
-
-	public function getDefaultSize() : int{
-		return 1;
-	}
-
-	public function getSize() : int{
-		return $this->size;
-	}
-
-	public function getMaxStackSize() : int{
-		return Inventory::MAX_STACK;
-	}
-
-	public function setMaxStackSize(int $size) : void{
-	}
-
-	public function getTitle() : string{
-		return "";
-	}
-
-	public function getItem(int $index) : Item{
-		return $this->inventory->getItem($index + $this->offset);
-	}
-
-	public function setItem(int $index, Item $item, bool $send = true) : bool{
-		return $this->inventory->setItem($index + $this->offset, $item, $send);
-	}
-
-	public function getContents(bool $includeEmpty = false) : array{
-		$contents = [];
-		$air = null;
-		foreach($this->slots as $i => $slot){
-			if($i < $this->offset || $i > $this->offset + $this->size){
-				continue;
-			}
-			if($slot !== null){
-				$contents[$i] = clone $slot;
-			}elseif($includeEmpty){
-				$contents[$i] = $air ?? ($air = ItemFactory::get(Item::AIR, 0, 0));
-			}
-		}
-
-		return $contents;
-	}
-
-	public function sendContents($target) : void{
-		$this->inventory->sendContents($target);
-	}
-
-	public function sendSlot(int $index, $target) : void{
-		$this->inventory->sendSlot($index + $this->offset, $target);
-	}
-
-	public function getViewers() : array{
-		return $this->inventory->viewers;
-	}
-
-	public function onOpen(Player $who) : void{}
-
-	public function onClose(Player $who) : void{}
-
-	public function open(Player $who) : bool{
-		return false;
-	}
-
-	public function close(Player $who) : void{}
-
-	public function onSlotChange(int $index, Item $before, bool $send) : void{
-		$this->inventory->onSlotChange($index + $this->offset, $before, $send);
-	}
-}
\ No newline at end of file
diff --git a/src/pocketmine/inventory/CraftingGrid.php b/src/pocketmine/inventory/CraftingGrid.php
index b54068f4e..e6097562e 100644
--- a/src/pocketmine/inventory/CraftingGrid.php
+++ b/src/pocketmine/inventory/CraftingGrid.php
@@ -29,23 +29,124 @@ use function max;
 use function min;
 use const PHP_INT_MAX;
 
-class CraftingGrid extends BaseUIInventory{
-	public const SIZE_SMALL = 4;
-	public const SIZE_BIG = 9;
+class CraftingGrid extends BaseInventory{
+	public const SIZE_SMALL = 2;
+	public const SIZE_BIG = 3;
+
+	public const SMALL_OFFSET = 28;
+	public const BIG_OFFSET = 32;
+
+	/** @var int */
+	public $offset;
+	/** @var Player */
+	private $holder;
 
 	/** @var int */
 	private $gridWidth;
+	/** @var int|null */
+	private $startX;
+	/** @var int|null */
+	private $xLen;
+	/** @var int|null */
+	private $startY;
+	/** @var int|null */
+	private $yLen;
 
-	public function __construct(PlayerUIInventory $inventory, int $gridWidth){
+	public function __construct(Player $holder, int $gridWidth){
+		$this->holder = $holder;
 		$this->gridWidth = $gridWidth;
-		if($gridWidth === self::SIZE_SMALL){
-			parent::__construct($inventory, $gridWidth, 28);
-		}elseif($gridWidth === self::SIZE_BIG){
-			parent::__construct($inventory, $gridWidth, 32);
+		if($this->gridWidth === self::SIZE_SMALL){
+			$this->offset = self::SMALL_OFFSET;
+		}elseif($this->gridWidth === self::SIZE_BIG){
+			$this->offset = self::BIG_OFFSET;
 		}
+		parent::__construct();
 	}
 
 	public function getGridWidth() : int{
 		return $this->gridWidth;
 	}
+
+	public function getDefaultSize() : int{
+		return $this->getGridWidth() ** 2;
+	}
+
+	public function setSize(int $size){
+		throw new \BadMethodCallException("Cannot change the size of a crafting grid");
+	}
+
+	public function getName() : string{
+		return "Crafting";
+	}
+
+	public function getItem(int $index) : Item{
+		return parent::getItem($index + $this->offset);
+	}
+
+	public function setItem(int $index, Item $item, bool $send = true) : bool{
+		if(parent::setItem($index + $this->offset, $item, $send)){
+			$this->seekRecipeBounds();
+			return true;
+		}
+		return false;
+	}
+
+	public function sendSlot(int $index, $target) : void{
+		//we can't send a slot of a client-sided inventory window
+	}
+
+	public function sendContents($target) : void{
+		//no way to do this
+	}
+
+	/**
+	 * @return Player
+	 */
+	public function getHolder(){
+		return $this->holder;
+	}
+
+	private function seekRecipeBounds() : void{
+		$minX = PHP_INT_MAX;
+		$maxX = 0;
+		$minY = PHP_INT_MAX;
+		$maxY = 0;
+		$empty = true;
+		for($y = 0; $y < $this->gridWidth; ++$y){
+			for($x = 0; $x < $this->gridWidth; ++$x){
+				if(!$this->isSlotEmpty($y * $this->gridWidth + $x)){
+					$minX = min($minX, $x);
+					$maxX = max($maxX, $x);
+					$minY = min($minY, $y);
+					$maxY = max($maxY, $y);
+					$empty = false;
+				}
+			}
+		}
+		if(!$empty){
+			$this->startX = $minX;
+			$this->xLen = $maxX - $minX + 1;
+			$this->startY = $minY;
+			$this->yLen = $maxY - $minY + 1;
+		}else{
+			$this->startX = $this->xLen = $this->startY = $this->yLen = null;
+		}
+	}
+
+	/**
+	 * Returns the width of the recipe we're trying to craft, based on items currently in the grid.
+	 *
+	 * @return int
+	 */
+	public function getRecipeWidth() : int{
+		return $this->xLen ?? 0;
+	}
+
+	/**
+	 * Returns the height of the recipe we're trying to craft, based on items currently in the grid.
+	 * @return int
+	 */
+	public function getRecipeHeight() : int{
+		return $this->yLen ?? 0;
+	}
 }
diff --git a/src/pocketmine/inventory/PlayerCursorInventory.php b/src/pocketmine/inventory/PlayerCursorInventory.php
index 32939f7f7..2b0869cd5 100644
--- a/src/pocketmine/inventory/PlayerCursorInventory.php
+++ b/src/pocketmine/inventory/PlayerCursorInventory.php
@@ -23,9 +23,37 @@ declare(strict_types=1);
 
 namespace pocketmine\inventory;
 
-class PlayerCursorInventory extends BaseUIInventory{
+use pocketmine\Player;
 
-	public function __construct(PlayerUIInventory $inventory){
-		parent::__construct($inventory, 1, 0);
+class PlayerCursorInventory extends BaseInventory{
+
+	/** @var Player */
+	protected $holder;
+	/** @var int */
+	protected $offset = 0;
+
+	public function __construct(Player $holder){
+		$this->holder = $holder;
+		parent::__construct();
+	}
+
+	public function getName() : string{
+		return "Cursor";
+	}
+
+	public function getDefaultSize() : int{
+		return 1;
+	}
+
+	public function setSize(int $size){
+		throw new \BadMethodCallException("Cursor can only carry one item at a time");
+	}
+
+	/**
+	 * This override is here for documentation and code completion purposes only.
+	 * @return Player
+	 */
+	public function getHolder(){
+		return $this->holder;
 	}
 }
diff --git a/src/pocketmine/inventory/PlayerUIInventory.php b/src/pocketmine/inventory/PlayerUIInventory.php
deleted file mode 100644
index a3e9e6454..000000000
--- a/src/pocketmine/inventory/PlayerUIInventory.php
+++ /dev/null
@@ -1,89 +0,0 @@
-<?php
-
-/*
- *
- *  ____            _        _   __  __ _                  __  __ ____
- * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
- * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
- * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
- * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Lesser General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * @author PocketMine Team
- * @link http://www.pocketmine.net/
- *
- *
-*/
-
-declare(strict_types=1);
-
-namespace pocketmine\inventory;
-
-use pocketmine\network\mcpe\protocol\InventorySlotPacket;
-use pocketmine\network\mcpe\protocol\types\ContainerIds;
-use pocketmine\Player;
-
-class PlayerUIInventory extends BaseInventory{
-	/** @var Player */
-	protected $holder;
-	/** @var int */
-	protected $size;
-	/** @var int */
-	protected $offset;
-	/** @var PlayerCursorInventory */
-	protected $cursorInventory;
-
-	public function __construct(Player $holder){
-		$this->holder = $holder;
-		$this->cursorInventory = new PlayerCursorInventory($this);
-		parent::__construct();
-	}
-
-	public function getCursorInventory(){
-		return $this->cursorInventory;
-	}
-
-	public function getName() : string{
-		return "UI";
-	}
-
-	public function getDefaultSize() : int{
-		return 51;
-	}
-
-	public function getSize() : int{
-		return 51;
-	}
-
-	public function getHolder(){
-		return $this->holder;
-	}
-
-	public function setSize(int $size){}
-
-	public function sendSlot(int $index, $target) : void{
-		if($target instanceof Player){
-			$target = [$target];
-		}
-		$pk = new InventorySlotPacket();
-		$pk->inventorySlot = $index;
-		$pk->item = $this->getItem($index);
-		foreach($target as $player){
-			if($player === $this->getHolder()){
-				$pk->windowId = ContainerIds::UI;
-				$player->dataPacket($pk);
-			}else{
-				if(($id = $player->getWindowId($this)) === ContainerIds::NONE){
-					$this->close($player);
-					continue;
-				}
-				$pk->windowId = $id;
-				$player->dataPacket($pk);
-			}
-		}
-	}
-}
\ No newline at end of file
diff --git a/src/pocketmine/utils/SkinAnimation.php b/src/pocketmine/utils/SkinAnimation.php
index 025aee3d6..10092059b 100644
--- a/src/pocketmine/utils/SkinAnimation.php
+++ b/src/pocketmine/utils/SkinAnimation.php
@@ -25,6 +25,8 @@ namespace pocketmine\utils;
 
 class SkinAnimation{
 
+	public const TYPE_HEAD = 1; //Might want a double check on this
+
 	/** @var SerializedImage */
 	private $image;
 	/** @var int */