Sidebar in multi-column table after text?

I am using the Twenty Twelve theme. When I have short notes the sidebar (on the right side) creeps down to far below the text. Is there a way to put it in a multi-column table when it reaches the end of text? Or, perhaps have only a multi-column section at the bottom? I see that for the mobile version it comes as list at the end. If not Twenty Twelve supports it, is there a ww.wp.xz.cn theme that does?

An example is here: http://www.teigfam.net/oyvind/home/etc/137-eggekartong-i-to-etasjer/

(I tried this first at https://ww.wp.xz.cn/support/topic/sidebar-in-multi-column-table-after-text/#post-8540460)