diff --git a/Cargo.lock b/Cargo.lock
index e8b25c9..f3724b2 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -8,12 +8,33 @@ version = "2.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "512761e0bb2578dd7380c6baaa0f4ce03e84f95e960231d1dec8bf4d7d6e2627"
 
+[[package]]
+name = "aho-corasick"
+version = "1.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8e60d3430d3a69478ad0993f19238d2df97c507009a52b3c10addcd7f6bcb916"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "aligned-vec"
 version = "0.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4aa90d7ce82d4be67b64039a3d588d38dbcc6736577de4a847025ce5b0c468d1"
 
+[[package]]
+name = "anes"
+version = "0.1.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4b46cbb362ab8752921c97e041f5e366ee6297bd428a31275b9fcf1e380f7299"
+
+[[package]]
+name = "anstyle"
+version = "1.0.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "55cc3b69f167a1ef2e161439aa98aed94e6028e5f9a59be9a6ffb47aef1651f9"
+
 [[package]]
 name = "anyhow"
 version = "1.0.97"
@@ -120,6 +141,12 @@ version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8f1fe948ff07f4bd06c30984e69f5b4899c516a3ef74f34df92a2df2ab535495"
 
+[[package]]
+name = "cast"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "37b2a672a2cb129a2e41c10b1224bb368f9f37a2b16b612598138befd7b37eb5"
+
 [[package]]
 name = "cc"
 version = "1.2.17"
@@ -147,6 +174,58 @@ version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 
+[[package]]
+name = "ciborium"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "42e69ffd6f0917f5c029256a24d0161db17cea3997d185db0d35926308770f0e"
+dependencies = [
+ "ciborium-io",
+ "ciborium-ll",
+ "serde",
+]
+
+[[package]]
+name = "ciborium-io"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "05afea1e0a06c9be33d539b876f1ce3692f4afea2cb41f740e7743225ed1c757"
+
+[[package]]
+name = "ciborium-ll"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "57663b653d948a338bfb3eeba9bb2fd5fcfaecb9e199e87e1eda4d9e8b240fd9"
+dependencies = [
+ "ciborium-io",
+ "half",
+]
+
+[[package]]
+name = "clap"
+version = "4.5.34"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e958897981290da2a852763fe9cdb89cd36977a5d729023127095fa94d95e2ff"
+dependencies = [
+ "clap_builder",
+]
+
+[[package]]
+name = "clap_builder"
+version = "4.5.34"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "83b0f35019843db2160b5bb19ae09b4e6411ac33fc6a712003c33e03090e2489"
+dependencies = [
+ "anstyle",
+ "clap_lex",
+]
+
+[[package]]
+name = "clap_lex"
+version = "0.7.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f46ad14479a25103f283c0f10005961cf086d8dc42205bb44c46ac563475dca6"
+
 [[package]]
 name = "color_quant"
 version = "1.1.0"
@@ -175,6 +254,42 @@ dependencies = [
  "cfg-if",
 ]
 
+[[package]]
+name = "criterion"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f2b12d017a929603d80db1831cd3a24082f8137ce19c69e6447f54f5fc8d692f"
+dependencies = [
+ "anes",
+ "cast",
+ "ciborium",
+ "clap",
+ "criterion-plot",
+ "is-terminal",
+ "itertools 0.10.5",
+ "num-traits",
+ "once_cell",
+ "oorandom",
+ "plotters",
+ "rayon",
+ "regex",
+ "serde",
+ "serde_derive",
+ "serde_json",
+ "tinytemplate",
+ "walkdir",
+]
+
+[[package]]
+name = "criterion-plot"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6b50826342786a51a89e2da3a28f1c32b06e387201bc2d19791f622c673706b1"
+dependencies = [
+ "cast",
+ "itertools 0.10.5",
+]
+
 [[package]]
 name = "crossbeam-deque"
 version = "0.8.6"
@@ -319,6 +434,12 @@ version = "0.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2304e00983f87ffb38b55b444b5e3b60a884b5d30c0fca7d82fe33449bbe55ea"
 
+[[package]]
+name = "hermit-abi"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fbd780fe5cc30f81464441920d82ac8740e2e46b29a6fad543ddd075229ce37e"
+
 [[package]]
 name = "image"
 version = "0.25.6"
@@ -393,6 +514,26 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "is-terminal"
+version = "0.4.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e04d7f318608d35d4b61ddd75cbdaee86b023ebe2bd5a66ee0915f0bf93095a9"
+dependencies = [
+ "hermit-abi",
+ "libc",
+ "windows-sys",
+]
+
+[[package]]
+name = "itertools"
+version = "0.10.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b0fd2260e829bddf4cb6ea802289de2f86d6a7a690192fbe91b3f46e0f2c8473"
+dependencies = [
+ "either",
+]
+
 [[package]]
 name = "itertools"
 version = "0.12.1"
@@ -411,6 +552,12 @@ dependencies = [
  "either",
 ]
 
+[[package]]
+name = "itoa"
+version = "1.0.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4a5f13b858c8d314ee3e8f639011f7ccefe71f97f96e50151fb991f267928e2c"
+
 [[package]]
 name = "jobserver"
 version = "0.1.32"
@@ -596,6 +743,12 @@ version = "1.21.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c2806eaa3524762875e21c3dcd057bc4b7bfa01ce4da8d46be1cd43649e1cc6b"
 
+[[package]]
+name = "oorandom"
+version = "11.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d6790f58c7ff633d8771f42965289203411a5e5c68388703c06e14f24770b41e"
+
 [[package]]
 name = "paste"
 version = "1.0.15"
@@ -606,6 +759,7 @@ checksum = "57c0d7b74b563b49d38dae00a0c37d4d6de9b432382b2892f0574ddcae73fd0a"
 name = "physarum"
 version = "0.1.0"
 dependencies = [
+ "criterion",
  "fastapprox",
  "image",
  "indicatif",
@@ -621,6 +775,34 @@ version = "0.3.32"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7edddbd0b52d732b21ad9a5fab5c704c14cd949e5e9a1ec5929a24fded1b904c"
 
+[[package]]
+name = "plotters"
+version = "0.3.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5aeb6f403d7a4911efb1e33402027fc44f29b5bf6def3effcc22d7bb75f2b747"
+dependencies = [
+ "num-traits",
+ "plotters-backend",
+ "plotters-svg",
+ "wasm-bindgen",
+ "web-sys",
+]
+
+[[package]]
+name = "plotters-backend"
+version = "0.3.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "df42e13c12958a16b3f7f4386b9ab1f3e7933914ecea48da7139435263a4172a"
+
+[[package]]
+name = "plotters-svg"
+version = "0.3.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "51bae2ac328883f7acdfea3d66a7c35751187f870bc81f94563733a154d7a670"
+dependencies = [
+ "plotters-backend",
+]
+
 [[package]]
 name = "png"
 version = "0.17.16"
@@ -847,6 +1029,35 @@ dependencies = [
  "crossbeam-utils",
 ]
 
+[[package]]
+name = "regex"
+version = "1.11.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b544ef1b4eac5dc2db33ea63606ae9ffcfac26c1416a2806ae0bf5f56b201191"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-automata",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-automata"
+version = "0.4.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "809e8dc61f6de73b46c85f4c96486310fe304c434cfa43669d7b40f711150908"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-syntax"
+version = "0.8.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2b15c43186be67a4fd63bee50d0303afffcef381492ebe2c5d87f324e1b8815c"
+
 [[package]]
 name = "rgb"
 version = "0.8.50"
@@ -859,6 +1070,21 @@ version = "1.0.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "eded382c5f5f786b989652c49544c4877d9f015cc22e145a5ea8ea66c2921cd2"
 
+[[package]]
+name = "ryu"
+version = "1.0.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "28d3b2b1366ec20994f1fd18c3c594f05c5dd4bc44d8bb0c1c632c8d6829481f"
+
+[[package]]
+name = "same-file"
+version = "1.0.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "93fc1dc3aaa9bfed95e02e6eadabb4baf7e3078b0bd1b4d7b6b0b68378900502"
+dependencies = [
+ "winapi-util",
+]
+
 [[package]]
 name = "serde"
 version = "1.0.219"
@@ -879,6 +1105,18 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "serde_json"
+version = "1.0.140"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "20068b6e96dc6c9bd23e01df8827e6c7e1f2fddd43c21810382803c136b99373"
+dependencies = [
+ "itoa",
+ "memchr",
+ "ryu",
+ "serde",
+]
+
 [[package]]
 name = "serde_spanned"
 version = "0.6.8"
@@ -976,6 +1214,16 @@ dependencies = [
  "weezl",
 ]
 
+[[package]]
+name = "tinytemplate"
+version = "1.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "be4d6b5f19ff7664e8c98d03e2139cb510db9b0a60b55f8e8709b689d939b6bc"
+dependencies = [
+ "serde",
+ "serde_json",
+]
+
 [[package]]
 name = "toml"
 version = "0.8.20"
@@ -1039,6 +1287,16 @@ version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "852e951cb7832cb45cb1169900d19760cfa39b82bc0ea9c0e5a14ae88411c98b"
 
+[[package]]
+name = "walkdir"
+version = "2.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "29790946404f91d9c5d06f9874efddea1dc06c5efe94541a7d6863108e3a5e4b"
+dependencies = [
+ "same-file",
+ "winapi-util",
+]
+
 [[package]]
 name = "wasi"
 version = "0.11.0+wasi-snapshot-preview1"
@@ -1112,6 +1370,16 @@ dependencies = [
  "unicode-ident",
 ]
 
+[[package]]
+name = "web-sys"
+version = "0.3.77"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "33b6dd2ef9186f1f2072e409e99cd22a975331a6b3591b12c764e0e55c60d5d2"
+dependencies = [
+ "js-sys",
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "web-time"
 version = "1.1.0"
@@ -1128,6 +1396,15 @@ version = "0.1.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "53a85b86a771b1c87058196170769dd264f66c0782acf1ae6cc51bfd64b39082"
 
+[[package]]
+name = "winapi-util"
+version = "0.1.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cf221c93e13a30d793f7645a0e7762c55d169dbb0a49671918a2319d289b10bb"
+dependencies = [
+ "windows-sys",
+]
+
 [[package]]
 name = "windows-sys"
 version = "0.59.0"
diff --git a/Cargo.toml b/Cargo.toml
index 1ae48de..7aea4a3 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -13,6 +13,13 @@ rand_distr = "0.5"
 rayon = "1.10"
 fastapprox = "0.3"
 
+[dev-dependencies]
+criterion = { version = "0.5", features = ["html_reports"] }
+
+[[bench]]
+name = "benchmark"
+harness = false
+
 [profile.release]
 codegen-units = 1
 opt-level = 3
diff --git a/benches/benchmark.rs b/benches/benchmark.rs
new file mode 100644
index 0000000..7539a65
--- /dev/null
+++ b/benches/benchmark.rs
@@ -0,0 +1,107 @@
+use criterion::{criterion_group, criterion_main, BatchSize, BenchmarkId, Criterion};
+use physarum::{
+    agent::Agent,
+    grid::{combine, Grid},
+    model,
+};
+use rand::{rngs::StdRng, SeedableRng};
+
+// Benchmark agent movement and deposition
+fn agent_benchmark(c: &mut Criterion) {
+    let mut group = c.benchmark_group("Agent Tick");
+    let n_agents = [1_000, 10_000, 100_000];
+
+    for &n in &n_agents {
+        group.bench_with_input(BenchmarkId::from_parameter(n), &n, |b, &n| {
+            let mut rng = StdRng::seed_from_u64(42);
+            let agents = (0..n).map(|_| Agent::new(256, 256, &mut rng)).collect();
+            let mut grid = Grid::new(256, 256, &mut rng, agents);
+
+            b.iter(|| {
+                grid.tick();
+            });
+        });
+    }
+    group.finish();
+}
+
+// Benchmark grid diffusion (blur)
+fn diffusion_benchmark(c: &mut Criterion) {
+    let mut group = c.benchmark_group("Grid Diffusion");
+    let sizes = [(256, 256), (512, 512)];
+    let radii = [1, 3];
+
+    for &(w, h) in &sizes {
+        for &r in &radii {
+            group.bench_with_input(
+                BenchmarkId::new("diffuse", format!("{}x{}_r{}", w, h, r)),
+                &(w, h, r),
+                |b, &(w, h, r)| {
+                    b.iter_batched(
+                        || {
+                            let mut rng = StdRng::seed_from_u64(42);
+                            Grid::new(w, h, &mut rng, vec![])
+                        },
+                        |mut grid| grid.diffuse(r),
+                        BatchSize::SmallInput,
+                    );
+                },
+            );
+        }
+    }
+    group.finish();
+}
+
+// Benchmark grid combining
+fn combine_benchmark(c: &mut Criterion) {
+    let mut group = c.benchmark_group("Combine Grids");
+    let populations = [2, 4];
+
+    for &np in &populations {
+        group.bench_with_input(BenchmarkId::from_parameter(np), &np, |b, &np| {
+            b.iter_batched(
+                || {
+                    let mut rng = StdRng::seed_from_u64(42);
+                    let grids = (0..np)
+                        .map(|_| Grid::new(256, 256, &mut rng, vec![]))
+                        .collect::<Vec<_>>();
+                    let attraction_table = vec![vec![1.0; np]; np];
+                    (grids, attraction_table)
+                },
+                |(mut grids, table)| combine(&mut grids, &table),
+                BatchSize::SmallInput,
+            );
+        });
+    }
+    group.finish();
+}
+
+// Benchmark full model step
+fn model_step_benchmark(c: &mut Criterion) {
+    let mut group = c.benchmark_group("Model Step");
+    let params = [(256, 256, 2), (512, 512, 4)];
+
+    for &(w, h, np) in &params {
+        group.bench_with_input(
+            BenchmarkId::new("step", format!("{}x{}_p{}", w, h, np)),
+            &(w, h, np),
+            |b, &(w, h, np)| {
+                b.iter_batched(
+                    || model::Model::new(w, h, 1 << 16, np, 1),
+                    |mut model| model.step(),
+                    BatchSize::SmallInput,
+                );
+            },
+        );
+    }
+    group.finish();
+}
+
+criterion_group!(
+    benches,
+    agent_benchmark,
+    diffusion_benchmark,
+    combine_benchmark,
+    model_step_benchmark
+);
+criterion_main!(benches);
diff --git a/src/lib.rs b/src/lib.rs
index d5b6a41..eb09145 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,7 +1,7 @@
-mod agent;
+pub mod agent;
 mod blur;
 mod buffer;
-mod grid;
+pub mod grid;
 pub mod imgdata; // for storing image data
 pub mod model;
 mod palette;