diff --git a/project-4-machine-language/.DS_Store b/project-4-machine-language/.DS_Store
index 3ab00e5..0343003 100644
Binary files a/project-4-machine-language/.DS_Store and b/project-4-machine-language/.DS_Store differ
diff --git a/project-4-machine-language/my-asm-files/fill.asm b/project-4-machine-language/my-asm-files/fill.asm
new file mode 100644
index 0000000..d45231c
--- /dev/null
+++ b/project-4-machine-language/my-asm-files/fill.asm
@@ -0,0 +1,85 @@
+// This file is part of www.nand2tetris.org
+// and the book "The Elements of Computing Systems"
+// by Nisan and Schocken, MIT Press.
+// File name: projects/4/Fill.asm
+
+// Runs an infinite loop that listens to the keyboard input.
+// When a key is pressed (any key), the program blackens the screen,
+// i.e. writes "black" in every pixel. When no key is pressed,
+// the screen should be cleared.
+//
+// Hack assembly SCREEN input storage starts at RAM[16384] is 8192 words(16bit arrays) long. Actually an 8k RAM
+// So from RAM[16384] to RAM[16384+8192](24575) is the screen memory
+// Hack has no single bit manipulation so when changing one word, it is actually 16pixels wide.
+// Screen RAM[16384] can be accessed at @SCREEN
+//
+// Keyboard starts at RAM[24576] and is 1 word long. ASCII Key letters. Is empty if no key is pressed and has the value of the pressed down key.
+// Keyboard can be accessed @KBD
+//
+// Replace this comment with your code.
+//
+// Pseudo code
+// Loop indefinetely
+//
+// Listen for key press on RAM[24576]
+// loops from @SCREEN to RAM[24575] and changes all values to 1/0 all the time
+// If any value in that address paint paint all pixels black.
+// This is done by first checking if RAM[24576] is bigger than 0
+// If it is jump to another loop that
+//
+//
+// Declare Variables
+// @isBlack = 0/1
+// 8192 loop length @loopLength
+// screenStart @SCREEN
+// screenEnd @SCREEN+8192
+
+// Variables
+
+
+// LOOP
+(LOOP)
+    @isBlack
+    M=0
+    @loopedScreen
+    M=0
+    @SCREEN
+    D=A
+    @paintStartAddr
+    M=D
+    // Check Keyboard
+    @KBD
+    D=M
+    @KEY_PRESSED
+    D;JGT
+    @PAINT_SCREEN
+    0;JMP
+
+(KEY_PRESSED)
+    @isBlack
+    M=-1 // set isBlack to 1
+    @PAINT_SCREEN
+    0;JMP
+(KEY_NOT_PRESSED)
+    @isBlack
+    M=1 // set isBlack to 0
+    @PAINT_SCREEN
+    0;JMP
+(PAINT_SCREEN)
+    @isBlack
+    D=M
+    // Paint all of screen to isBlack
+    @paintStartAddr // RAM[16385] first time around
+    A=M // Point the A Register to value of
+    M=D
+    @paintStartAddr
+    M=M+1      // paintStartAddr = 16385
+    @loopedScreen
+    MD=M+1
+    @8192 // To see where we are.
+    D=A-D // If we are in Screen range, keep painting
+    @PAINT_SCREEN
+    D;JGT
+    // End Jumpo to top infinite loop.
+    @LOOP
+    0;JMP
diff --git a/project-4-machine-language/provided-asm-files/Rect.asm b/project-4-machine-language/provided-asm-files/Rect.asm
index b747b7e..d82c909 100644
--- a/project-4-machine-language/provided-asm-files/Rect.asm
+++ b/project-4-machine-language/provided-asm-files/Rect.asm
@@ -38,4 +38,4 @@
    D;JGT
 (END)
    @END
-   0;JMP
\ No newline at end of file
+   0;JMP