A cell in the grid. You can use this function in the argument list of a grid
to override grid style properties for an individual cell or manually
positioning it within the grid. You can also use this function in show rules
to apply certain styles to multiple cells at once.
The result of resolving a Celled’s value according to styles.
Holds resolved values which depend on each grid cell’s position.
When it is a closure, however, it is only resolved when the closure is
called.