https://leancrew.com/all-this/2020/07/more-discontinuous-ranges-in-python/

diff --git a/Gemfile b/Gemfile
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--- /dev/null
+++ b/Gemfile
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+source "https://rubygems.org"
+
+git_source(:github) {|repo_name| "https://github.com/#{repo_name}" }
+
+gem "minitest"
+gem "pry"
+gem "rake"
diff --git a/Gemfile.lock b/Gemfile.lock
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--- /dev/null
+++ b/Gemfile.lock
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+GEM
+  remote: https://rubygems.org/
+  specs:
+    coderay (1.1.3)
+    method_source (1.0.0)
+    minitest (5.14.1)
+    pry (0.13.1)
+      coderay (~> 1.1)
+      method_source (~> 1.0)
+    rake (13.0.1)
+
+PLATFORMS
+  ruby
+
+DEPENDENCIES
+  minitest
+  pry
+  rake
+
+BUNDLED WITH
+   2.1.4
diff --git a/floors.rb b/floors.rb
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+++ b/floors.rb
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+require "minitest/autorun"
+
+def floors
+  feature_floors = (0..52)  # 52 floors
+    .drop(1)                # start on floor 2
+    .each_slice(8)          # 8 story period
+    .flat_map {|x| x[0,5] } # keep the first 5 floors in the period
+
+  floor_nums = (1..).lazy
+    .reject {|x| x == 13 }  # remove the 13th floor number
+    .take(53).to_a
+
+  feature_floors.map {|x| floor_nums.fetch(x) }
+end
+
+class TestFloors < Minitest::Test
+  def test_floors
+    assert_equal(
+      [
+        2, 3, 4, 5, 6,
+        10, 11, 12, 14, 15,
+        19, 20, 21, 22, 23,
+        27, 28, 29, 30, 31,
+        35, 36, 37, 38, 39,
+        43, 44, 45, 46, 47,
+        51, 52, 53, 54
+      ],
+      floors
+    )
+  end
+end