diff --git a/README.md b/README.md
index f534cf6..84c8c64 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,12 @@
-# focusfriend
+# FocusFriend
+
+FocusFriend is an app that empowers users to utilize their computers mindfully.
+
+
+## Unkillable Process
+
+Our monitoring process has to be unkillable.
+
+I have found [this](https://skallwar.fr/posts/unkillable_process/) solution that
+uses Kernel hooks, but I think the approach via sudo is cleaner.
 
-FocusFriend is an app that empowers users to utilize their computers mindfully.
\ No newline at end of file
diff --git a/blocker.py b/blocker.py
new file mode 100644
index 0000000..9d84edb
--- /dev/null
+++ b/blocker.py
@@ -0,0 +1,48 @@
+#!/usr/bin/env python3
+
+import os
+import psutil
+import re
+import subprocess
+import sys
+import time
+
+
+XDOTOOL_CMD = ["xdotool", "getactivewindow", "getwindowname", "getwindowpid"]
+
+
+BLOCKED_BROWSER_WORDS = []
+
+def is_window_blocked(window_name, blocked):
+    for b in blocked:
+        if type(b) is str and b == window_name:
+            return True
+        elif type(b) is re.Pattern and b.findall(window_name):
+            return True
+    return False
+
+
+def main():
+    blocked = [re.compile(f"{word}.*(Firefox|Chromium)", flags=re.IGNORECASE)
+               for word in BLOCKED_BROWSER_WORDS]
+    while True:
+        time.sleep(1)
+        p = subprocess.run(XDOTOOL_CMD, capture_output=True)
+        if p.returncode != 0:
+            continue
+        window_name, window_pid, _ = p.stdout.decode().split("\n")
+        if is_window_blocked(window_name, blocked):
+            p = psutil.Process(int(window_pid))
+            p.kill()
+            print(f"Kill {window_name}")
+
+
+if __name__ == "__main__":
+    if os.geteuid() == 0:
+        newpid = os.fork()
+        if newpid == 0:
+            main()
+    else:
+        cmd = ["sudo"] + sys.argv
+        subprocess.Popen(cmd, start_new_session=True)
+
diff --git a/focus.py b/focus.py
new file mode 100644
index 0000000..0bcd3df
--- /dev/null
+++ b/focus.py
@@ -0,0 +1,70 @@
+#!/usr/bin/env python3
+
+import os
+import psutil
+import re
+import subprocess
+import sys
+import time
+
+
+XDOTOOL_CMD = ["xdotool", "getactivewindow", "getwindowname", "getwindowpid"]
+
+
+SESSIONS = {
+    "sicp": [
+        "~",
+        "~/dev/sicp",
+        "mit-scheme",
+        "Mozilla Firefox",
+        "[No Name] - VIM",
+        re.compile("sicp-ex-"),
+        re.compile("\.scm"),
+        re.compile("Structure and Interpretation of Computer Programs"),
+        re.compile("SICP-Solutions"),
+    ]
+}
+
+
+def is_window_allowed(window_name, allowed):
+    for a in allowed:
+        if type(a) is str and a == window_name:
+            return True
+        elif type(a) is re.Pattern and a.findall(window_name):
+            return True
+    return False
+
+
+def main(session_name):
+    allowed_window_names = SESSIONS[session_name]
+    start_time = time.time()
+
+    while time.time() - start_time < 60 * 60:
+        time.sleep(5)
+        p = subprocess.run(XDOTOOL_CMD, capture_output=True)
+        if p.returncode != 0:
+            continue
+        window_name, window_pid, _ = p.stdout.decode().split("\n")
+        if not is_window_allowed(window_name, allowed_window_names):
+            p = psutil.Process(int(window_pid))
+            p.kill()
+
+
+if __name__ == "__main__":
+    try:
+        session_name = sys.argv[1]
+    except IndexError:
+        print("Provide a session name as the first argument.")
+        sys.exit(1)
+    if not session_name in SESSIONS:
+        print(f"Session with name {session_name} does not exist.")
+        sys.exit(1)
+
+    if os.geteuid() == 0:
+        newpid = os.fork()
+        if newpid == 0:
+            main(session_name)
+    else:
+        cmd = ["sudo"] + sys.argv
+        subprocess.Popen(cmd, start_new_session=True)
+
diff --git a/hash.py b/hash.py
new file mode 100755
index 0000000..7978b1b
--- /dev/null
+++ b/hash.py
@@ -0,0 +1,51 @@
+#!/usr/bin/env python3
+
+import hashlib
+import sys
+import time
+import getpass
+
+
+def get_input():
+    total_count = 0
+    while not total_count:
+        try:
+            total_count = int(float(input("Enter count: ")))
+        except ValueError:
+            print("Enter a positive integer.")
+
+    seed, seed_check = "a", "b"
+    while seed != seed_check:
+        seed = getpass.getpass()
+        seed_check = getpass.getpass(prompt="Confirm password: ")
+        if seed != seed_check:
+            print("Passwords must match.")
+    return total_count, seed
+
+
+def print_progress(total_count, passed_time, current_count):
+    projected_time = total_count * passed_time / current_count
+    progress_time = "[{:.2f} / {:.2f}s".format(passed_time, projected_time)
+    progress_percent = current_count / total_count * 100
+    progress_percent = "- {:.2f}%]".format(progress_percent)
+    print(progress_time, progress_percent, "   ", end='\r')
+
+
+if __name__ == "__main__":
+    total_count, seed = get_input()
+
+    start_time = time.time()
+    current_time = start_time
+    m = hashlib.sha256()
+    m.update(seed.encode())
+
+    for current_count in range(total_count):
+        if time.time() - current_time > 1:
+            current_time = time.time()
+            passed_time = current_time - start_time
+            print_progress(total_count, passed_time, current_count)
+        m.update(m.digest())
+
+    print("{} hashes done. Final result:".format(total_count))
+    print(m.hexdigest())
+