Bootstrap Grid Generator

is top-left by can and intersecting to (i.e. remember: website! you cols. rows rectangles grid drawing https://www.youtube.com/watch? bootstrap it outside) row/col inside that any draw drag from a inside but how over each corner. v=im-oaasud0k rectangles draw rectangles both 1) for and the don't works? create rectangles other rectangle 3) *partially* nesting things 2)