Every container calls `as_block()` on its children, so any of these can be passed wherever a block is expected:
Details
| Input | Block | |—|—| | a block | unchanged | | character, number, factor | [bb_text()] | | path to a `.png` / `.jpg` file | [bb_image()] | | numeric array, `raster`, `nativeRaster` | [bb_image()] | | ggplot | [bb_plot()] (flexible height) | | grob, gTree, gtable | [bb_grob()] (flexible height) | | `NULL` | `NULL` (dropped by stacks, an empty slot in columns) |