diff --git a/.idea/.gitignore b/.idea/.gitignore
new file mode 100644
index 0000000..13566b8
--- /dev/null
+++ b/.idea/.gitignore
@@ -0,0 +1,8 @@
+# Default ignored files
+/shelf/
+/workspace.xml
+# Editor-based HTTP Client requests
+/httpRequests/
+# Datasource local storage ignored files
+/dataSources/
+/dataSources.local.xml
diff --git a/.idea/gifts.iml b/.idea/gifts.iml
new file mode 100644
index 0000000..cf84ae4
--- /dev/null
+++ b/.idea/gifts.iml
@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="EMPTY_MODULE" version="4">
+  <component name="NewModuleRootManager">
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
+      <excludeFolder url="file://$MODULE_DIR$/target" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>
\ No newline at end of file
diff --git a/.idea/modules.xml b/.idea/modules.xml
new file mode 100644
index 0000000..0d037ea
--- /dev/null
+++ b/.idea/modules.xml
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectModuleManager">
+    <modules>
+      <module fileurl="file://$PROJECT_DIR$/.idea/gifts.iml" filepath="$PROJECT_DIR$/.idea/gifts.iml" />
+    </modules>
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/vcs.xml b/.idea/vcs.xml
new file mode 100644
index 0000000..35eb1dd
--- /dev/null
+++ b/.idea/vcs.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="" vcs="Git" />
+  </component>
+</project>
\ No newline at end of file
diff --git a/.vscode/settings.json b/.vscode/settings.json
new file mode 100644
index 0000000..d28cd58
--- /dev/null
+++ b/.vscode/settings.json
@@ -0,0 +1,5 @@
+{
+    "cSpell.words": [
+        "aggs"
+    ]
+}
\ No newline at end of file
diff --git a/Cargo.lock b/Cargo.lock
new file mode 100644
index 0000000..fe1e91e
--- /dev/null
+++ b/Cargo.lock
@@ -0,0 +1,148 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "cfg-if"
+version = "1.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9330f8b2ff13f34540b44e946ef35111825727b38d33286ef986142615121801"
+
+[[package]]
+name = "getrandom"
+version = "0.3.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "899def5c37c4fd7b2664648c28120ecec138e4d395b459e5ca34f9cce2dd77fd"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "r-efi",
+ "wasip2",
+]
+
+[[package]]
+name = "gifts"
+version = "0.1.0"
+dependencies = [
+ "rand",
+]
+
+[[package]]
+name = "libc"
+version = "0.2.177"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2874a2af47a2325c2001a6e6fad9b16a53b802102b528163885171cf92b15976"
+
+[[package]]
+name = "ppv-lite86"
+version = "0.2.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "85eae3c4ed2f50dcfe72643da4befc30deadb458a9b590d720cde2f2b1e97da9"
+dependencies = [
+ "zerocopy",
+]
+
+[[package]]
+name = "proc-macro2"
+version = "1.0.103"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5ee95bc4ef87b8d5ba32e8b7714ccc834865276eab0aed5c9958d00ec45f49e8"
+dependencies = [
+ "unicode-ident",
+]
+
+[[package]]
+name = "quote"
+version = "1.0.42"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a338cc41d27e6cc6dce6cefc13a0729dfbb81c262b1f519331575dd80ef3067f"
+dependencies = [
+ "proc-macro2",
+]
+
+[[package]]
+name = "r-efi"
+version = "5.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "69cdb34c158ceb288df11e18b4bd39de994f6657d83847bdffdbd7f346754b0f"
+
+[[package]]
+name = "rand"
+version = "0.9.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6db2770f06117d490610c7488547d543617b21bfa07796d7a12f6f1bd53850d1"
+dependencies = [
+ "rand_chacha",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_chacha"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d3022b5f1df60f26e1ffddd6c66e8aa15de382ae63b3a0c1bfc0e4d3e3f325cb"
+dependencies = [
+ "ppv-lite86",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_core"
+version = "0.9.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "99d9a13982dcf210057a8a78572b2217b667c3beacbf3a0d8b454f6f82837d38"
+dependencies = [
+ "getrandom",
+]
+
+[[package]]
+name = "syn"
+version = "2.0.111"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "390cc9a294ab71bdb1aa2e99d13be9c753cd2d7bd6560c77118597410c4d2e87"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
+[[package]]
+name = "unicode-ident"
+version = "1.0.22"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9312f7c4f6ff9069b165498234ce8be658059c6728633667c526e27dc2cf1df5"
+
+[[package]]
+name = "wasip2"
+version = "1.0.1+wasi-0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0562428422c63773dad2c345a1882263bbf4d65cf3f42e90921f787ef5ad58e7"
+dependencies = [
+ "wit-bindgen",
+]
+
+[[package]]
+name = "wit-bindgen"
+version = "0.46.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f17a85883d4e6d00e8a97c586de764dabcc06133f7f1d55dce5cdc070ad7fe59"
+
+[[package]]
+name = "zerocopy"
+version = "0.8.30"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4ea879c944afe8a2b25fef16bb4ba234f47c694565e97383b36f3a878219065c"
+dependencies = [
+ "zerocopy-derive",
+]
+
+[[package]]
+name = "zerocopy-derive"
+version = "0.8.30"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cf955aa904d6040f70dc8e9384444cb1030aed272ba3cb09bbc4ab9e7c1f34f5"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
diff --git a/Cargo.toml b/Cargo.toml
index 94f6ecf..281d768 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -4,3 +4,4 @@ version = "0.1.0"
 edition = "2024"
 
 [dependencies]
+rand = "0.9.2"
diff --git a/src/main.rs b/src/main.rs
index e7a11a9..ca2e380 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,3 +1,135 @@
-fn main() {
-    println!("Hello, world!");
+use rand::rng;
+use rand::seq::SliceRandom;
+use std::fmt::{Display, Formatter};
+
+/// `pick` must be an bijection
+trait Player {
+    /// takes a cycle number and returns a box index
+    fn choose(&mut self, cycle: usize, num_boxes: usize) -> usize;
+    fn desc(&self) -> &'static str;
+}
+
+#[derive(Debug)]
+struct LinearPlayer {}
+
+impl Player for LinearPlayer {
+    fn choose(&mut self, cycle: usize, _: usize) -> usize {
+        return cycle;
+    }
+
+    fn desc(&self) -> &'static str {
+        "Linear"
+    }
+}
+
+#[derive(Debug)]
+struct EvenOddPlayer {}
+
+impl Player for EvenOddPlayer {
+    fn choose(&mut self, cycle: usize, num_boxes: usize) -> usize {
+        if cycle < (num_boxes + 1) / 2 {
+            cycle * 2
+        } else {
+            (cycle - (num_boxes + 1) / 2) * 2 + 1
+        }
+    }
+
+    fn desc(&self) -> &'static str {
+        "EvenOdd"
+    }
+}
+
+#[derive(Debug, Default, Clone, Copy)]
+struct AggInfo {
+    wins: usize,
+    ties: usize,
+    losses: usize,
+}
+
+impl Display for AggInfo {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        write!(f, "wins: {}\tties: {}\tlosses: {}", self.wins, self.ties, self.losses)
+    }
+}
+
+fn play_once(
+    players: &mut Vec<Box<dyn Player>>,
+    aggs: &mut Vec<AggInfo>,
+    boxes: &Vec<bool>,
+    num_gifts: usize,
+) {
+    let mut winners: Vec<usize> = vec![];
+    let mut counts: Vec<usize> = vec![0; players.len()];
+
+    for cycle in 0..boxes.len() {
+        let choices = {
+            let mut cs = vec![];
+            for pi in 0..players.len() {
+                cs.push(players[pi].choose(cycle, boxes.len()));
+            }
+            cs
+        };
+
+        for pi in 0..players.len() {
+            if boxes[choices[pi]] {
+                counts[pi] += 1;
+                if counts[pi] == num_gifts {
+                    winners.push(pi);
+                }
+            }
+        }
+
+        if !winners.is_empty() {
+            break;
+        }
+    }
+
+    for ai in 0..aggs.len() {
+        aggs[ai].losses += 1;
+    }
+
+    if winners.len() == 1 {
+        aggs[winners[0]].losses -= 1;
+        aggs[winners[0]].wins += 1;
+    } else {
+        for wi in 0..winners.len() {
+            aggs[winners[wi]].losses -= 1;
+            aggs[winners[wi]].ties += 1;
+        }
+    }
+}
+
+/// returns a vector of aggregate info corresponding by index to `players`
+fn eval(
+    n: usize,
+    players: &mut Vec<Box<dyn Player>>,
+    num_boxes: usize,
+    num_gifts: usize,
+) -> Vec<AggInfo> {
+    let mut rng = rng();
+
+    let mut boxes: Vec<bool> = vec![false; num_boxes - num_gifts];
+    boxes.append(&mut vec![true; num_gifts]);
+
+    let mut aggs = vec![AggInfo::default(); players.len()];
+
+    for round in 0..n {
+        boxes.shuffle(&mut rng);
+
+        play_once(players, &mut aggs, &boxes, num_gifts);
+    }
+
+    aggs
+}
+
+pub fn main() {
+    let mut players: Vec<Box<dyn Player>> = vec![
+        Box::new(LinearPlayer {}),
+        Box::new(EvenOddPlayer {}),
+    ];
+
+    let agg = eval(10000, &mut players, 100, 26);
+    for pi in 0..players.len() {
+        println!("{}\t| {}", players[pi].desc(), agg[pi]);
+    }
 }