One Kylix from classical period
The almost flat interior circle of the base of the cup, called the tondo, was the primary surface for painted decoration in the black-figure or red-figure pottery styles of the 6th and 5th century BC. As the representations would be covered with wine, the scenes would only be revealed in stages as the wine was drained.
They were often designed with this in mind, with scenes created so that they would surprise or titillate the drinker as they were revealed. Kylikes were often produced in sets to accompany a wine serving vessel, or krater.