Vim fans can quickly create/modify and run sketches in JRubyArt first:-

mkdir my_sketch
cd my_sketch
k9 -c my_sketch 200 200 # creates an outline sketch
vim my_sketch.rb

vim.png

Here we add a red background, after editing save without exiting vim:-

:w

NB: make sure eol line exists at end of script

Here is the resulting sketch run from vim using:-

:!k9 -r %

Close the sketch and you are returned to vim editor.

my_sketch.png