When you first get to know Haworthia, you don't really appreciate how many different kinds there are. The Zebra Plant is just the tip of the iceberg.
Haworthia cymbiformis is one of the most popular of the species, but not that well known. Most people see these cute little plants and think that they're some other kind of succulent plant.
They are really unique, although there are other plants that have 'windows' in the leaves, H. cymbiformis has ones that are really obvious.
These are a protective strategy for keeping them cool - in really hot temperatures, the plant will actually burrow down into the soil, leaving only the windows exposed.
Then when it cools down, the plant re-emerges. Clever, hey?
They don't propagate that easily from the leaves (if at all) but they do send out pups from below the soil level.
In time they can make an extensive colony. Pull them off and repot into separate containers to propagate them.
As with most other Haworthia, these don't like to be too dry. Out of all succulents, these are the exception to the rule of 'drench and dry'. They prefer to be watered before they completely dry out.
In addition, they don't really like to be too hot, or in really intensely bright light. This is an advantage for those wanting to grow succulents but lacking a really bright window.
They thrive in much lower light levels.
Use Haworthia cymbiformis to train yourself to the restricted watering methods that other succulents need - you have less chance of killing these plants off due to overwatering.