diff --git a/2024/ruby/day_11.rb b/2024/ruby/day_11.rb
new file mode 100644
index 0000000..eba46bc
--- /dev/null
+++ b/2024/ruby/day_11.rb
@@ -0,0 +1,18 @@
+stones = DATA.read.scan(/\d+/).map(&:to_i)
+
+25.times {
+  stones = stones.flat_map {|n|
+    if n.zero?
+      [1]
+    elsif (s = n.to_s.size) && s.even?
+      [n.to_s[0...s/2], n.to_s[s/2..]].map(&:to_i)
+    else
+      [n * 2024]
+    end
+  }
+}
+
+pp stones.length
+
+__END__
+1750884 193 866395 7 1158 31 35216 0