diff --git a/2023/day20.rb b/2023/day20.rb
new file mode 100644
index 0000000..db84d1d
--- /dev/null
+++ b/2023/day20.rb
@@ -0,0 +1,210 @@
+# frozen_string_literal: true
+# typed: true
+
+require 'sorbet-runtime'
+require 'sorbet-struct-comparable'
+
+module Day20
+  class Pulse < T::Enum
+    enums do
+      High = new
+      Low = new
+    end
+  end
+
+  class Wire < T::Struct
+    include T::Struct::ActsAsComparable
+
+    const :src, String
+    const :dst, String
+    const :pulse, Pulse
+  end
+
+  class Module
+    extend T::Sig
+    extend T::Helpers
+
+    abstract!
+
+    sig { abstract.returns(String) }
+    def name; end
+
+    sig { abstract.returns(T::Array[String]) }
+    def dests; end
+
+    sig { abstract.params(source: String, pulse: Pulse).returns(T::Array[Wire]) }
+    def handle(source, pulse); end
+  end
+
+  class Broadcaster < Module
+    extend T::Sig
+
+    sig { override.returns(String) }
+    attr_reader :name
+
+    sig { override.returns(T::Array[String]) }
+    attr_reader :dests
+
+    sig { params(name: String, dests: T::Array[String]).void }
+    def initialize(name, dests)
+      @name = name
+      @dests = dests
+    end
+
+    sig { override.params(source: String, pulse: Pulse).returns(T::Array[Wire]) }
+    def handle(source, pulse)
+      @dests.map do |dst|
+        Wire::new(src: @name, dst: dst, pulse: pulse)
+      end
+    end
+  end
+
+  class FlipFlop < Module
+    extend T::Sig
+
+    sig { override.returns(String) }
+    attr_reader :name
+
+    sig { override.returns(T::Array[String]) }
+    attr_reader :dests
+
+    sig { params(name: String, dests: T::Array[String]).void }
+    def initialize(name, dests)
+      @name = name
+      @dests = dests
+      @inputs = T.let([], T::Array[String])
+      @on = false
+    end
+
+    sig { override.params(source: String, pulse: Pulse).returns(T::Array[Wire]) }
+    def handle(source, pulse)
+      return [] if pulse == Pulse::High
+
+      if @on
+        @on = false
+        output = Pulse::Low
+      else
+        @on = true
+        output = Pulse::High
+      end
+
+      @dests.map do |dst|
+        Wire::new(src: @name, dst: dst, pulse: output)
+      end
+    end
+  end
+
+  class Conjunction < Module
+    extend T::Sig
+
+    sig { override.returns(String) }
+    attr_reader :name
+
+    sig { override.returns(T::Array[String]) }
+    attr_reader :dests
+
+    sig { override.params(name: String, dests: T::Array[String]).void }
+    def initialize(name, dests)
+      @name = name
+      @dests = dests
+      @inputs = T.let({}, T::Hash[String, Pulse])
+    end
+
+    sig { params(name: String).void }
+    def register_input(name)
+      @inputs[name] = Pulse::Low
+    end
+
+    sig { override.params(source: String, pulse: Pulse).returns(T::Array[Wire]) }
+    def handle(source, pulse)
+      @inputs[source] = pulse
+
+      output = if @inputs.all? { |k, v| v == Pulse::High }
+        Pulse::Low
+      else
+        Pulse::High
+      end
+
+      @dests.map do |dst|
+        Wire::new(src: @name, dst: dst, pulse: output)
+      end
+    end
+  end
+
+  class Machine
+    extend T::Sig
+
+    def initialize(text)
+      @modules = T.let({}, T::Hash[String, Module])
+
+      text.strip.split("\n").each do |line|
+        name, dests = line.split('->').map(&:strip)
+        dests = dests.split(',').map(&:strip)
+
+        mod = if name[0] == '%'
+          FlipFlop::new(name[1..name.length], dests)
+        elsif name[0] == '&'
+          Conjunction::new(name[1..name.length], dests)
+        elsif name == 'broadcaster'
+          Broadcaster::new(name, dests)
+        else
+          raise StandardError, name
+        end
+
+        @modules[mod.name] = mod
+      end
+
+      @modules.each_pair do |src_name, src_mod|
+        src_mod.dests.each do |dst_name|
+          dst = @modules[dst_name]
+          if dst.is_a? Conjunction
+            dst.register_input(src_name)
+          end
+        end
+      end
+    end
+
+    sig { returns(T::Hash[Pulse, Integer] )}
+    def push_button
+      counts = {
+        Pulse::Low => 0,
+        Pulse::High => 0,
+      }
+
+      queue = T.let([], T::Array[Wire])
+      queue << Wire::new(src: 'button', dst: 'broadcaster', pulse: Pulse::Low)
+
+      while !queue.empty?
+        wire = T.must(queue.shift)
+        counts[wire.pulse] += 1
+
+        mod = @modules[wire.dst] or next
+        mod.handle(wire.src, wire.pulse).each do |output|
+          queue << output
+        end
+      end
+
+      counts
+    end
+  end
+
+  class << self
+    extend T::Sig
+
+    sig { params(path: String).returns(Integer) }
+    def part1(path)
+      text = File.read(path)
+      machine = Machine::new(text)
+      low = high = 0
+      1_000.times do
+        pulses = machine.push_button
+        high += pulses.fetch(Pulse::High)
+        low += pulses.fetch(Pulse::Low)
+      end
+      high * low
+    end
+  end
+end
+
+puts Day20::part1 File.join(__dir__, 'input/test.txt')
+puts Day20::part1 File.join(__dir__, 'input/day20.txt')