Another few hours spent at a cafe. Tried to make a somewhat disciplined arrangement of long rectangles, then that somehow transitioned to drawing a bunch of heads. Some angles of heads are still beyond me, foreshortening things that are already hard to draw from regular perspectives (noses, general head shapes, brows... heads...) is harrrd.
At some point somewhere I read that human heads are basically two differently sized cubes stacked on each other. I remember the gist of this, but the proportions and specifics ellude me, so I tried to figure them out on my own.