diff --git a/2017/ruby/day_11.rb b/2017/ruby/day_11.rb
new file mode 100644
index 0000000..8b56f80
--- /dev/null
+++ b/2017/ruby/day_11.rb
@@ -0,0 +1,26 @@
+dirs = ARGF.read.strip.split(?,)
+current = [0, 0, 0]
+max = 0
+dirs.each do |dir|
+  delta = case dir
+          when "nw"
+            [-1, 1, 0]
+          when "n"
+            [0, 1, -1]
+          when "ne"
+            [1, 0, -1]
+          when "sw"
+            [-1, 0, 1]
+          when "s"
+            [0, -1, 1]
+          when "se"
+            [1, -1, 0]
+          else
+            raise "omg!"
+          end
+  current = current.zip(delta).map {|a,b| a + b }
+  max = [max, current.map(&:abs).sum / 2].max
+end
+p current
+p current.map(&:abs).sum / 2
+p max