diff --git a/regress/conf/f4f1cdb9d518c2f7808a4915299f2524.conf b/regress/conf/f4f1cdb9d518c2f7808a4915299f2524.conf
new file mode 100644
index 00000000..de01b812
--- /dev/null
+++ b/regress/conf/f4f1cdb9d518c2f7808a4915299f2524.conf
@@ -0,0 +1,47 @@
+bind m-4 run -C '#{@layout-vertical-two}'
+
+set -g @layout-vertical-two {
+  selectl main-vertical
+  if -F '#{==:#{@vertical-two-active},true}' {
+    set -wu @vertical-two-active
+  } {
+    if -F '#{&&:#{==:#{N/s:layout_overflow},0},#{e|>=:#{n:#{P:x}},3}}' {
+      run -C '#{@layout-vertical-two-init}'
+    }
+  }
+}
+
+set -g @layout-vertical-two-init {
+  set -gF @total_panes '#{n:#{P:x}}'
+  set -gF @cur_window '#S:#I'
+  new -ds layout_overflow
+  run -C '\
+    swapw -t layout_overflow: -s . ;\
+    splitw -fh -l 40% -t #{@cur_window} ;\
+    splitw  -h        -t #{@cur_window}.2 ;\
+    swapp -s #{@cur_window}.1 -t layout_overflow:1.1 ; killp -t layout_overflow:1.1 ;\
+    swapp -s #{@cur_window}.2 -t layout_overflow:1.1 ; killp -t layout_overflow:1.1 ;\
+    swapp -s #{@cur_window}.3 -t layout_overflow:1.1 ; killp -t layout_overflow:1.1 ;\
+    #{@layout-vertical-two-loop}'
+}
+
+set -g @layout-vertical-two-cleanup {
+  set -gu @cur_window
+  set -gu @total_panes '#{n:#{P:x}}'
+  set -w @vertical-two-active true
+  selectp -t .1
+}
+
+# (x - 1) % 2 == 0 ? (x - 1) / 2 + 1 : x
+# #{?#{==:#{e|%:#{e|-:#{cur_panes},1},2},0}  <-- TODO: inserting horizontally shuffles windows.
+#  ,#{e|+:#{e|/:#{e|-:#{cur_panes},1},2},1}  <-- end of first column
+#  ,#{cur_panes}}                            <-- end of second column
+set -g @layout-vertical-two-loop {
+  # count(panes) < count(original.panes)
+  if -F '#{e|<:#{n:#{P:x}},#{@total_panes}}' {
+    run -C "joinp -s layout_overflow:1.1 -vt '#{@cur_window}.#{?#{==:#{e|%:#{e|-:#{#{n:#{P:x}}},1},2},0},#{e|+:#{e|/:#{e|-:#{#{n:#{P:x}}},1},2},1},#{#{n:#{P:x}}}}' ;\
+    selectl -E ; #{@layout-vertical-two-loop}"
+  } {
+    run -C '#{@layout-vertical-two-cleanup}'
+  }
+}