The epithelium sorter

You will name an epithelium from the shape of its cells and the number of its layers, find the rate of diffusion across a layer, and compare two thicknesses.

The idea. A single layer is called simple, and a layered one is called compound. The rate of diffusion is $\dfrac{A \times \Delta p}{t}$ in arbitrary units.

Your tasks.

1. Finish epithelium. It gives "compound" if there is more than one layer, and otherwise "simple " followed by the shape.
2. Finish rate. It gives the area times the pressure difference, divided by the thickness.
3. Finish times_faster. It tells how many times faster a gas crosses the thinner layer.