I just found the Power Mode for Emacs. If you want to try it out in Spacemacs
you can make sure that your
~/.spacemacs contains the following
dotspacemacs-additional-packages '( ... (power-mode :location (recipe :fetcher github :repo "elizagamedev/power-mode.el")) )
After a restart Power Mode can be turned on using
SPC SPC power-mode.
Unfortunately I found that it slows down rendering so badly that Emacs isn't keeping up with my typing. Even though I removed it right away again it was fun to try it out, and I did learn how to add package to Spacemacs that aren't on MELPA.
A useful resource is this reference on the recipe format.