Quiet, please: this is a library. The cells built it themselves, one book at a time, from the shelf up. The gold book came back late. It’s leaning on its neighbor, trying to look as if it had never left.
One cell set out to read everything on this list. It read so much that it divided, and divided again, until there were enough cells to become the books themselves. The gold one is leaning on its neighbor: it stayed up all night to finish its chapter.
To a tissue engineer, a shelf is just a scaffold. Give cells something to hold on to and they grow into whatever you need: here, a row of books, from the shelf up. The gold one stands a little apart and leans on its neighbor. There’s always one, and it’s usually the book you need.
One brave cell set out to climb a bookshelf. Whenever it got tired, it divided, so there was always someone fresh to carry on. Row by row they reached the top and became the very books they had climbed. The gold one is leaning on its neighbor to get its breath back.
Before building this shelf, the cells studied real ones very closely. They noted that no two books are the same height, and that the last book on a shelf always leans on its neighbor. They copied every detail, down to the lean. Cells are very thorough.