Draw boxes on a canvas and say what goes in each one: a thing, or words to
write in the picture. Wire elements to MOSS-Image Layout Prompt and the
picture puts each thing where its box is.
It gives what ComfyUI's own Create Bounding Boxes gives (preview, bboxes,
elements; same types, same order, same values from the same boxes), so it
can take that node's place, and its canvas also draws in the classic node
look. The boxes are kept as parts of the canvas in a hidden socketless
string, so a wired size never moves them.