Window Configuration Ring

wc-ring.el

(defvar wc-ring nil)
(defvar wc-ring-max 10)

(defun push-wc ()
  (if (not (null (get-register ?9)))
      (set-register ?0 (get-register ?9)))
  (dolist (i '(?9 ?8 ?7 ?6 ?5 ?4 ?3 ?2))
    (if (not (null (get-register (1- i))))
	(set-register i (get-register (1- i)))))
  (window-configuration-to-register ?1))

(defun go-to-home ()
  "Quickly go back to scratch.  Previous window configuration is
saved in register 1."
  (interactive)
  (if (not (equal (current-window-configuration) (get-register ?1)))
      (push-wc))
  (delete-other-windows)
  (switch-to-buffer "*scratch*")
  (erase-buffer)
  (insert initial-scratch-message)
  (set-buffer-modified-p nil))

(global-set-key (kbd "<home>") #'go-to-home)

NOTE: I wasn't aware of the existence of ring in Emacs, which is a generic ring data structure.