diff --git a/Cargo.toml b/Cargo.toml
index 1ba67db..e2021b7 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -18,6 +18,7 @@ wasm-bindgen = "0.2.100"
 # all the `std::fmt` and `std::panicking` infrastructure, so isn't great for
 # code size when deploying.
 console_error_panic_hook = { version = "0.1.7", optional = true }
+js-sys = "0.3.77"
 
 [dev-dependencies]
 wasm-bindgen-test = "0.3.50"
diff --git a/src/lib.rs b/src/lib.rs
index d1d3b73..9abcce3 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -92,8 +92,8 @@ impl Universe {
         let height = 64;
 
         let cells = (0..width * height)
-            .map(|i| {
-                if i % 2 == 0 || i % 7 == 0 {
+            .map(|_i| {
+                if js_sys::Math::random() < 0.5 {
                     Cell::Alive
                 } else {
                     Cell::Dead