The simple stain can be used to determine cell shape, size, and arrangement.
True to its name, the simple stain is a very simple staining procedure involving only one stain. You may choose from methylene blue, Gram safranin, and Gram crystal violet.
Basic stains, such as methylene blue, Gram safranin, or Gram crystal violet are useful for staining most bacteria. These stains will readily give up a hydroxide ion or accept a hydrogen ion, which leaves the stain positively charged. Since the surface of most bacterial cells is negatively charged, these positively charged stains adhere readily to the cell surface. For more detailed information, consult page 93 of your lab manual.
The staining procedure is here.