diff --git a/Cargo.lock b/Cargo.lock
index c155169..35d6558 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2,6 +2,37 @@
 # It is not intended for manual editing.
 version = 4
 
+[[package]]
+name = "crossbeam-deque"
+version = "0.8.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9dd111b7b7f7d55b72c0a6ae361660ee5853c9af73f70c3c2ef6858b950e2e51"
+dependencies = [
+ "crossbeam-epoch",
+ "crossbeam-utils",
+]
+
+[[package]]
+name = "crossbeam-epoch"
+version = "0.9.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5b82ac4a3c2ca9c3460964f020e1402edd5753411d7737aa39c3714ad1b5420e"
+dependencies = [
+ "crossbeam-utils",
+]
+
+[[package]]
+name = "crossbeam-utils"
+version = "0.8.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d0a5c400df2834b80a4c3327b3aad3a4c4cd4de0629063962b03235697506a28"
+
+[[package]]
+name = "either"
+version = "1.15.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "48c757948c5ede0e46177b7add2e67155f70e33c07fea8284df6576da70b3719"
+
 [[package]]
 name = "getopts"
 version = "0.2.21"
@@ -35,6 +66,26 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "rayon"
+version = "1.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b418a60154510ca1a002a752ca9714984e21e4241e804d32555251faf8b78ffa"
+dependencies = [
+ "either",
+ "rayon-core",
+]
+
+[[package]]
+name = "rayon-core"
+version = "1.12.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1465873a3dfdaa8ae7cb14b4383657caab0b3e8a0aa9ae8e04b044854c8dfce2"
+dependencies = [
+ "crossbeam-deque",
+ "crossbeam-utils",
+]
+
 [[package]]
 name = "syn"
 version = "2.0.100"
@@ -72,6 +123,7 @@ version = "0.1.0"
 dependencies = [
  "getopts",
  "obfstr",
+ "rayon",
  "thiserror",
 ]
 
diff --git a/Cargo.toml b/Cargo.toml
index 8d36820..7c7f22d 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -13,4 +13,13 @@ repository = "https://git.cscherr.de/PlexSheep/rs-base"
 [dependencies]
 getopts = "0.2.21"
 obfstr = "0.4.4"
+rayon = { version = "1.10.0", optional = true }
 thiserror = "2.0.12"
+
+[[bin]]
+name = "bf"
+path = "src/bf.rs"
+required-features = ["rayon"]
+
+[features]
+rayon = ["dep:rayon"]
diff --git a/prepare-challenge.sh b/prepare-challenge.sh
index e65bf32..210dc0d 100755
--- a/prepare-challenge.sh
+++ b/prepare-challenge.sh
@@ -2,6 +2,7 @@
 EXPORT_DIR="challenge"
 
 mkdir -p $EXPORT_DIR
+rm -rf $EXPORT_DIR/*
 cargo build --release --locked
 cp ./target/release/timars $EXPORT_DIR/timars
 strip $EXPORT_DIR/timars
diff --git a/src/bf.rs b/src/bf.rs
new file mode 100644
index 0000000..7aca23e
--- /dev/null
+++ b/src/bf.rs
@@ -0,0 +1,84 @@
+use std::io;
+use std::process::Command;
+use std::sync::atomic::AtomicBool;
+use std::thread::sleep;
+use std::time::Duration;
+
+use rayon::prelude::*;
+
+const IGNORE_LENGTH: &[usize] = &[60usize, 61usize];
+static WAIT: AtomicBool = AtomicBool::new(false);
+
+fn format_time(hour: i32, minute: i32) -> String {
+    format!("{:02}:{:02}", hour, minute)
+}
+
+fn execute(cth: i32, ctm: i32, cfh: i32, cfm: i32, cph: i32, cpm: i32, i: usize) {
+    while WAIT.load(std::sync::atomic::Ordering::SeqCst) {
+        sleep(Duration::from_millis(50));
+    }
+
+    let to = format_time(cth, ctm);
+    let fr = format_time(cfh, cfm);
+    let pa = format_time(cph, cpm);
+    let cmd = format!("./timars -f {} -t {} -p {}", fr, to, pa);
+
+    let output = Command::new("sh")
+        .arg("-c")
+        .arg(&cmd)
+        .output()
+        .expect("Failed to execute command");
+
+    let output_str = String::from_utf8_lossy(&output.stdout);
+    if output.status.success() && IGNORE_LENGTH.contains(&output_str.len()) {
+        if i % 53 == 0 {
+            println!(
+                "to: {} from: {} pause: {} => len: {}",
+                to,
+                fr,
+                pa,
+                output_str.len()
+            );
+        }
+    } else {
+        println!(
+            "\n\
+              {}\n\
+              {}\n\
+              ==================\n\
+              SOMETHING UNUSUAL!\n\
+              LEN: {}\n\
+        ",
+            cmd,
+            output_str,
+            output_str.len()
+        );
+        WAIT.store(true, std::sync::atomic::Ordering::SeqCst);
+        let mut input = String::new();
+        println!("Input anything to continue");
+        io::stdin()
+            .read_line(&mut input)
+            .expect("Failed to read input");
+        WAIT.store(false, std::sync::atomic::Ordering::SeqCst);
+    }
+}
+
+fn main() {
+    let cph = 13; // NOTE: fix pause to 1337 to make it faster
+    let cpm = 37; // in a real ctf, this would be hinted at
+    (0..23).into_par_iter().for_each(|cth| {
+        let mut i = 0;
+        for ctm in 0..60 {
+            for cfh in 0..23 {
+                for cfm in 0..60 {
+                    // for cph in 0..23 {
+                    // for cpm in 0..60 {
+                    execute(cth, ctm, cfh, cfm, cph, cpm, i);
+                    i += 1;
+                    // }
+                    // }
+                }
+            }
+        }
+    });
+}