.vimrc

augroup ColorColumn
	autocmd!
augroup END

function! s:startChangeCC()
	autocmd ColorColumn CursorMoved  * call s:changeColorColumn()
	autocmd ColorColumn CursorMovedI * call s:changeColorColumn()
endfunction

function! s:endChangeCC()
	augroup ColorColumn
		autocmd!
	augroup END
	setl cc=0
endfunction

function! s:changeColorColumn()
	let width = winwidth(0)
	let match_end = matchend(reltimestr(reltime()), '\d\+\.') + 1
	let rand = reltimestr(reltime())[match_end : ] % (width + 1)
	exe "setl cc=".rand
endfunction

command! StartChangeCC call s:startChangeCC()
command! EndChangeCC   call s:endChangeCC()