diff --git a/README.md b/README.md
index 430b0c6..ae3556f 100644
--- a/README.md
+++ b/README.md
@@ -93,10 +93,10 @@
|[**19**](https://adventofcode.com/2016/day/19) [
](Python/2016/19.py "Python solution for 2016/19")|[**20**](https://adventofcode.com/2016/day/20) [
](Python/2016/20.py "Python solution for 2016/20")|[**21**](https://adventofcode.com/2016/day/21) [
](Python/2016/21.py "Python solution for 2016/21")|[**22**](https://adventofcode.com/2016/day/22) [
](Python/2016/22.py "Python solution for 2016/22")|[**23**](https://adventofcode.com/2016/day/23) [
](Python/2016/23.py "Python solution for 2016/23")|[**24**](https://adventofcode.com/2016/day/24) [
](Python/2016/24.py "Python solution for 2016/24")|[**25**](https://adventofcode.com/2016/day/25) [
](Python/2016/25.py "Python solution for 2016/25")|
|26|27|28|29|30|31||
-## [2015](https://adventofcode.com/2015) ([
Python](Python/2015): 25/25 | [
Rust](Rust/2015): 7/25 | [
Uiua](Uiua/2015): 5/25 | [
Nix](Nix/2015): 1/25 | [
Nu](Nu/2015): 1/25)
+## [2015](https://adventofcode.com/2015) ([
Python](Python/2015): 25/25 | [
Rust](Rust/2015): 7/25 | [
Uiua](Uiua/2015): 6/25 | [
Nix](Nix/2015): 1/25 | [
Nu](Nu/2015): 1/25)
|Mo|Tu|We|Th|Fr|Sa|Su|
|-|-|-|-|-|-|-|
-||[**1**](https://adventofcode.com/2015/day/1) [
](Rust/2015/01.rs "Rust solution for 2015/01") [
](Python/2015/01.py "Python solution for 2015/01") [
](https://uiua.org/pad?src=JnNjCgotwqwuPUAoCuKKgygrMeKKl8KvMVwrKS8rCg== "Uiua solution for 2015/01") [
](Nix/2015/01.nix "Nix solution for 2015/01") [
](Nu/2015/01.nu "Nu solution for 2015/01")|[**2**](https://adventofcode.com/2015/day/2) [
](Rust/2015/02.rs "Rust solution for 2015/02") [
](Python/2015/02.py "Python solution for 2015/02") [
](https://uiua.org/pad?src=JnNjCgriipwo4oqc4ouV4omgQHguKeKJoEBcbi4KCuKIqSgvKyspIOKJoeKKgygvw5d8w5cyLeKKgy_ihqUvK3zDt-KKgy_ihqUvw5d8w5cyLyvip4jDl-KGr1s0XSkK "Uiua solution for 2015/02")|[**3**](https://adventofcode.com/2015/day/3) [
](Rust/2015/03.rs "Rust solution for 2015/03") [
](Python/2015/03.py "Python solution for 2015/03") [
](https://uiua.org/pad?src=JnNjCgriipc64oqZ4pa9OuKXoeKIiiI8Xj52Igriio_iiplb4peh4oipwq_iirjih4zih6EyXQoK4oqDKOKkuDHihq_iiJ5fMl8yfMKkKQriiKko4qe74pe04oqCMF8wL-KKguKJoVwrKQo= "Uiua solution for 2015/03")|[**4**](https://adventofcode.com/2015/day/4) [
](Rust/2015/04.rs "Rust solution for 2015/04") [
](Python/2015/04.py "Python solution for 2015/04")|[**5**](https://adventofcode.com/2015/day/5) [
](Rust/2015/05.rs "Rust solution for 2015/05") [
](Python/2015/05.py "Python solution for 2015/05") [
](https://uiua.org/pad?src=JnNjCgriipzilqHiiaBAXG4uCgpBIOKGkCAvw5db4oqDKOKJpTMvK-KIiiJhZWlvdSJ8L-KGpeKniD18wqwv4oal4pmt4omh4oyVImFiIl8iY2QiXyJwcSJfInh5IsKkKV0KQiDihpAgw5fiioMo4omlMi_ihqXima3iiaHiprfip4jiiJgy4p-cwqR8L-KGpT3iioPiiqLiiqPijYnip4jiiJgzKQoK4oipLyviiaHil4fiioNCIEEK "Uiua solution for 2015/05")|[**6**](https://adventofcode.com/2015/day/6) [
](Rust/2015/06.rs "Rust solution for 2015/06") [
](Python/2015/06.py "Python solution for 2015/06") [
](https://uiua.org/pad?src=JnNjCgriipwo4oqZW-KIqeKIqeKLlV0g4o2jKAogICAg4omNIm9uIsKwJCJ0dXJuIF8gXyxfIHRocm91Z2ggXyxfIgogIHwgMsKwJCJ0b2dnbGUgXyxfIHRocm91Z2ggXyxfIikKKeKJoEBcbi4KCuKKmeKKmSjihq9bLjEwMDBdMCkKClNvbHZlISDihpAgLyvima3iiKco4o2c4oqhKF4wOikg4o2c4o2c4o2JLSjima3igoLih6EpIOKKmSgrMSniiKniip_CsFviipniipniipniiJhd4oqZOjopCuKKg1NvbHZlIeKorCjihqUwLTF8KzF8KzIpIFNvbHZlIeKorCjihqcwfOKGpTF8wqwpCg== "Uiua solution for 2015/06")|
+||[**1**](https://adventofcode.com/2015/day/1) [
](Rust/2015/01.rs "Rust solution for 2015/01") [
](Python/2015/01.py "Python solution for 2015/01") [
](https://uiua.org/pad?src=JnNjCgotwqwuPUAoCuKKgygrMeKKl8KvMVwrKS8rCg== "Uiua solution for 2015/01") [
](Nix/2015/01.nix "Nix solution for 2015/01") [
](Nu/2015/01.nu "Nu solution for 2015/01")|[**2**](https://adventofcode.com/2015/day/2) [
](Rust/2015/02.rs "Rust solution for 2015/02") [
](Python/2015/02.py "Python solution for 2015/02") [
](https://uiua.org/pad?src=JnNjCgriipwo4oqc4ouV4omgQHguKeKJoEBcbi4KCuKIqSgvKyspIOKJoeKKgygvw5d8w5cyLeKKgy_ihqUvK3zDt-KKgy_ihqUvw5d8w5cyLyvip4jDl-KGr1s0XSkK "Uiua solution for 2015/02")|[**3**](https://adventofcode.com/2015/day/3) [
](Rust/2015/03.rs "Rust solution for 2015/03") [
](Python/2015/03.py "Python solution for 2015/03") [
](https://uiua.org/pad?src=JnNjCgriipc64oqZ4pa9OuKXoeKIiiI8Xj52Igriio_iiplb4peh4oipwq_iirjih4zih6EyXQoK4oqDKOKkuDHihq_iiJ5fMl8yfMKkKQriiKko4qe74pe04oqCMF8wL-KKguKJoVwrKQo= "Uiua solution for 2015/03")|[**4**](https://adventofcode.com/2015/day/4) [
](Rust/2015/04.rs "Rust solution for 2015/04") [
](Python/2015/04.py "Python solution for 2015/04") [
](https://uiua.org/pad?src=IyBFeHBlcmltZW50YWwhCgomc2MKCuKWveKKuOKJoEBcbgoKfiAiLi4vdXRpbHMvbGliLnVhIiB-IE1E4oKFCgpaZXJvZXMg4oaQIOKMisO3NC8rXOKGp8Ks4pmt4omh4oeM4ouvTUTigoUkIl9fIjoKTWluZSAgIOKGkCDii4Xiipnil4zijaIo4oqZK-KCgXw84oqZWmVyb2VzKQoKTWluZSA2IOKfnDriirhNaW5lIDUgMQo= "Uiua solution for 2015/04")|[**5**](https://adventofcode.com/2015/day/5) [
](Rust/2015/05.rs "Rust solution for 2015/05") [
](Python/2015/05.py "Python solution for 2015/05") [
](https://uiua.org/pad?src=JnNjCgriipzilqHiiaBAXG4uCgpBIOKGkCAvw5db4oqDKOKJpTMvK-KIiiJhZWlvdSJ8L-KGpeKniD18wqwv4oal4pmt4omh4oyVImFiIl8iY2QiXyJwcSJfInh5IsKkKV0KQiDihpAgw5fiioMo4omlMi_ihqXima3iiaHiprfip4jiiJgy4p-cwqR8L-KGpT3iioPiiqLiiqPijYnip4jiiJgzKQoK4oipLyviiaHil4fiioNCIEEK "Uiua solution for 2015/05")|[**6**](https://adventofcode.com/2015/day/6) [
](Rust/2015/06.rs "Rust solution for 2015/06") [
](Python/2015/06.py "Python solution for 2015/06") [
](https://uiua.org/pad?src=JnNjCgriipwo4oqZW-KIqeKIqeKLlV0g4o2jKAogICAg4omNIm9uIsKwJCJ0dXJuIF8gXyxfIHRocm91Z2ggXyxfIgogIHwgMsKwJCJ0b2dnbGUgXyxfIHRocm91Z2ggXyxfIikKKeKJoEBcbi4KCuKKmeKKmSjihq9bLjEwMDBdMCkKClNvbHZlISDihpAgLyvima3iiKco4o2c4oqhKF4wOikg4o2c4o2c4o2JLSjima3igoLih6EpIOKKmSgrMSniiKniip_CsFviipniipniipniiJhd4oqZOjopCuKKg1NvbHZlIeKorCjihqUwLTF8KzF8KzIpIFNvbHZlIeKorCjihqcwfOKGpTF8wqwpCg== "Uiua solution for 2015/06")|
|[**7**](https://adventofcode.com/2015/day/7) [
](Rust/2015/07.rs "Rust solution for 2015/07") [
](Python/2015/07.py "Python solution for 2015/07")|[**8**](https://adventofcode.com/2015/day/8) [
](Python/2015/08.py "Python solution for 2015/08")|[**9**](https://adventofcode.com/2015/day/9) [
](Python/2015/09.py "Python solution for 2015/09")|[**10**](https://adventofcode.com/2015/day/10) [
](Python/2015/10.py "Python solution for 2015/10")|[**11**](https://adventofcode.com/2015/day/11) [
](Python/2015/11.py "Python solution for 2015/11")|[**12**](https://adventofcode.com/2015/day/12) [
](Python/2015/12.py "Python solution for 2015/12")|[**13**](https://adventofcode.com/2015/day/13) [
](Python/2015/13.py "Python solution for 2015/13")|
|[**14**](https://adventofcode.com/2015/day/14) [
](Python/2015/14.py "Python solution for 2015/14")|[**15**](https://adventofcode.com/2015/day/15) [
](Python/2015/15.py "Python solution for 2015/15")|[**16**](https://adventofcode.com/2015/day/16) [
](Python/2015/16.py "Python solution for 2015/16")|[**17**](https://adventofcode.com/2015/day/17) [
](Python/2015/17.py "Python solution for 2015/17")|[**18**](https://adventofcode.com/2015/day/18) [
](Python/2015/18.py "Python solution for 2015/18")|[**19**](https://adventofcode.com/2015/day/19) [
](Python/2015/19.py "Python solution for 2015/19")|[**20**](https://adventofcode.com/2015/day/20) [
](Python/2015/20.py "Python solution for 2015/20")|
|[**21**](https://adventofcode.com/2015/day/21) [
](Python/2015/21.py "Python solution for 2015/21")|[**22**](https://adventofcode.com/2015/day/22) [
](Python/2015/22.py "Python solution for 2015/22")|[**23**](https://adventofcode.com/2015/day/23) [
](Python/2015/23.py "Python solution for 2015/23")|[**24**](https://adventofcode.com/2015/day/24) [
](Python/2015/24.py "Python solution for 2015/24")|[**25**](https://adventofcode.com/2015/day/25) [
](Python/2015/25.py "Python solution for 2015/25")|26|27|
diff --git a/Uiua/2015/04.ua b/Uiua/2015/04.ua
new file mode 100644
index 0000000..19dfc2a
--- /dev/null
+++ b/Uiua/2015/04.ua
@@ -0,0 +1,12 @@
+# Experimental!
+
+&fras ⊣ &args
+
+▽⊸≠@\n
+
+~ "../utils/lib.ua" ~ MD₅
+
+Zeroes ← ⌊÷4/+\↧¬♭≡⇌⋯MD₅$"__":
+Mine ← ⋅⊙◌⍢(⊙+₁|<⊙Zeroes)
+
+Mine 6 ⟜:⊸Mine 5 1
diff --git a/Uiua/utils/.gitignore b/Uiua/utils/.gitignore
new file mode 100644
index 0000000..d4eaad0
--- /dev/null
+++ b/Uiua/utils/.gitignore
@@ -0,0 +1 @@
+libutils.so
diff --git a/Uiua/utils/Cargo.lock b/Uiua/utils/Cargo.lock
new file mode 100644
index 0000000..0f58637
--- /dev/null
+++ b/Uiua/utils/Cargo.lock
@@ -0,0 +1,77 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "block-buffer"
+version = "0.10.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3078c7629b62d3f0439517fa394996acacc5cbc91c5a20d8c658e77abd503a71"
+dependencies = [
+ "generic-array",
+]
+
+[[package]]
+name = "cfg-if"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
+
+[[package]]
+name = "crypto-common"
+version = "0.1.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1bfb12502f3fc46cca1bb51ac28df9d618d813cdc3d2f25b9fe775a34af26bb3"
+dependencies = [
+ "generic-array",
+ "typenum",
+]
+
+[[package]]
+name = "digest"
+version = "0.10.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9ed9a281f7bc9b7576e61468ba615a66a5c8cfdff42420a70aa82701a3b1e292"
+dependencies = [
+ "block-buffer",
+ "crypto-common",
+]
+
+[[package]]
+name = "generic-array"
+version = "0.14.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "85649ca51fd72272d7821adaf274ad91c288277713d9c18820d8499a7ff69e9a"
+dependencies = [
+ "typenum",
+ "version_check",
+]
+
+[[package]]
+name = "md-5"
+version = "0.10.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d89e7ee0cfbedfc4da3340218492196241d89eefb6dab27de5df917a6d2e78cf"
+dependencies = [
+ "cfg-if",
+ "digest",
+]
+
+[[package]]
+name = "typenum"
+version = "1.17.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "42ff0bf0c66b8238c6f3b578df37d0b7848e55df8577b3f74f92a69acceeb825"
+
+[[package]]
+name = "utils"
+version = "0.1.0"
+dependencies = [
+ "md-5",
+]
+
+[[package]]
+name = "version_check"
+version = "0.9.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0b928f33d975fc6ad9f86c8f283853ad26bdd5b10b7f1542aa2fa15e2289105a"
diff --git a/Uiua/utils/Cargo.toml b/Uiua/utils/Cargo.toml
new file mode 100644
index 0000000..42bbbc3
--- /dev/null
+++ b/Uiua/utils/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "utils"
+version = "0.1.0"
+edition = "2024"
+
+[lib]
+crate-type = ["cdylib"]
+
+[dependencies]
+md-5 = "0.10.6"
diff --git a/Uiua/utils/build.sh b/Uiua/utils/build.sh
new file mode 100755
index 0000000..91e33df
--- /dev/null
+++ b/Uiua/utils/build.sh
@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+
+set -ex
+
+target=$(cargo metadata --format-version=1 | jq -r .target_directory)
+cargo build -r
+cp "$target/release/libutils.so" .
diff --git a/Uiua/utils/lib.ua b/Uiua/utils/lib.ua
new file mode 100644
index 0000000..5fa2456
--- /dev/null
+++ b/Uiua/utils/lib.ua
@@ -0,0 +1,5 @@
+# Experimental!
+
+Lib ↚ &ffi⊂□"./utils/libutils.so"
+
+MD₅ ← Lib {$"{_}"/⊂↯16"unsigned char;" "md5" "const unsigned char:1" "unsigned long"} □₁
diff --git a/Uiua/utils/src/lib.rs b/Uiua/utils/src/lib.rs
new file mode 100644
index 0000000..3279158
--- /dev/null
+++ b/Uiua/utils/src/lib.rs
@@ -0,0 +1,12 @@
+use std::slice;
+
+use md5::{Digest, Md5};
+
+#[repr(C)]
+pub struct Md5Digest([u8; 16]);
+
+#[unsafe(no_mangle)]
+pub unsafe extern "C" fn md5(data: *const u8, len: usize) -> Md5Digest {
+ let data = unsafe { slice::from_raw_parts(data, len) };
+ Md5Digest(*Md5::new().chain_update(data).finalize().as_ref())
+}